usb: add (move) CONFIG_USB_HOST to Kconfig

The meaning of CONFIG_USB in U-Boot is different from that in Linux.

As you see in drivers/usb/Kconfig of Linux, CONFIG_USB enables the
USB host controller support, while CONFIG_USB_SUPPORT is used to
enable the whole of the USB sub-system.

When I added CONFIG_USB into Kconfig by commit 6e7e9294d3 ("usb:
add basic USB configs in Kconfig"), I planned to follow the Linux's
convention, i.e. CONFIG_USB to enable/disable the USB host support.

Then, commit 68f7c5db2d ("usb: Generic USB Kconfig option, that
fits both host and gadget and comments") changed the logic of the
CONFIG_USB to point to the whole of the USB sub-system.  As a result,
currently we do not have an option for USB host.

This commit adds CONFIG_USB_HOST, which will be useful to compile
in the USB host support code.

CONFIG_USB_HOST is not referenced at all, but strangely some boards
define it in board headers.  I removed them because USB_HOST will be
selected in Kconfig going forward.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

include/configs/am43xx_evm.h

@@ -98,7 +98,6 @@
 
 #if defined(CONFIG_SPL_USB_HOST_SUPPORT) || !defined(CONFIG_SPL_BUILD)
 #define CONFIG_SYS_USB_FAT_BOOT_PARTITION		1
-#define CONFIG_USB_HOST
 #define CONFIG_USB_XHCI_OMAP
 #define CONFIG_USB_STORAGE
 #define CONFIG_SYS_USB_XHCI_MAX_ROOT_PORTS 2

include/configs/am57xx_evm.h

@@ -63,7 +63,6 @@
 #define CONFIG_SUPPORT_EMMC_BOOT
 
 /* USB xHCI HOST */
-#define CONFIG_USB_HOST
 #define CONFIG_USB_XHCI_OMAP
 #define CONFIG_USB_STORAGE
 #define CONFIG_SYS_USB_XHCI_MAX_ROOT_PORTS 2

include/configs/cm_t43.h

@@ -60,7 +60,6 @@
 #define CONFIG_SYS_RX_ETH_BUFFER	64
 
 /* USB support */
-#define CONFIG_USB_HOST
 #define CONFIG_USB_XHCI_OMAP
 #define CONFIG_USB_STORAGE
 #define CONFIG_SYS_USB_XHCI_MAX_ROOT_PORTS 2

include/configs/cm_t54.h

@@ -69,7 +69,6 @@
 #define CONFIG_SYS_SCSI_MAX_DEVICE	(CONFIG_SYS_SCSI_MAX_SCSI_ID * \
 						CONFIG_SYS_SCSI_MAX_LUN)
 /* USB UHH support options */
-#define CONFIG_USB_HOST
 #define CONFIG_USB_EHCI
 #define CONFIG_USB_EHCI_OMAP
 #define CONFIG_USB_STORAGE

include/configs/dra7xx_evm.h

@@ -209,7 +209,6 @@
 #define CONFIG_SUPPORT_EMMC_BOOT
 
 /* USB xHCI HOST */
-#define CONFIG_USB_HOST
 #define CONFIG_USB_XHCI_OMAP
 #define CONFIG_USB_STORAGE
 #define CONFIG_SYS_USB_XHCI_MAX_ROOT_PORTS 2

include/configs/duovero.h

@@ -29,7 +29,6 @@
 #define CONFIG_SYS_DEFAULT_LPDDR2_TIMINGS
 
 /* USB UHH support options */
-#define CONFIG_USB_HOST
 #define CONFIG_USB_EHCI
 #define CONFIG_USB_EHCI_OMAP
 #define CONFIG_USB_STORAGE

include/configs/omap4_panda.h

@@ -17,7 +17,6 @@
  */
 
 /* USB UHH support options */
-#define CONFIG_USB_HOST
 #define CONFIG_USB_EHCI
 #define CONFIG_USB_EHCI_OMAP
 #define CONFIG_USB_STORAGE

include/configs/omap5_uevm.h

@@ -88,7 +88,6 @@
 #define CONFIG_SYS_I2C_TCA642X_ADDR 0x22
 
 /* USB UHH support options */
-#define CONFIG_USB_HOST
 #define CONFIG_USB_EHCI
 #define CONFIG_USB_EHCI_OMAP
 #define CONFIG_USB_STORAGE