common: Move board_get_usable_ram_top() out of common.h

Move this function into init.h which seems to be designed for this sort
of thing. Also update the header to declare struct global_data so that it
can be included without global_data.h being needed.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>

arch/x86/cpu/broadwell/sdram.c

@@ -7,6 +7,7 @@
 
 #include <common.h>
 #include <dm.h>
+#include <init.h>
 #include <pci.h>
 #include <syscon.h>
 #include <asm/cpu.h>

arch/x86/cpu/coreboot/sdram.c

@@ -6,6 +6,7 @@
  */
 
 #include <common.h>
+#include <init.h>
 #include <asm/e820.h>
 #include <asm/arch/sysinfo.h>
 

arch/x86/cpu/efi/payload.c

@@ -8,6 +8,7 @@
 #include <cpu_func.h>
 #include <efi.h>
 #include <errno.h>
+#include <init.h>
 #include <usb.h>
 #include <asm/bootparam.h>
 #include <asm/e820.h>

arch/x86/cpu/efi/sdram.c

@@ -5,6 +5,7 @@
 
 #include <common.h>
 #include <efi.h>
+#include <init.h>
 #include <asm/u-boot-x86.h>
 
 DECLARE_GLOBAL_DATA_PTR;

arch/x86/cpu/intel_common/mrc.c

@@ -5,6 +5,7 @@
 
 #include <common.h>
 #include <dm.h>
+#include <init.h>
 #include <syscon.h>
 #include <asm/cpu.h>
 #include <asm/gpio.h>

arch/x86/cpu/ivybridge/sdram.c

@@ -12,6 +12,7 @@
 #include <common.h>
 #include <errno.h>
 #include <fdtdec.h>
+#include <init.h>
 #include <malloc.h>
 #include <net.h>
 #include <rtc.h>

arch/x86/cpu/qemu/dram.c

@@ -4,6 +4,7 @@
  */
 
 #include <common.h>
+#include <init.h>
 #include <asm/post.h>
 #include <asm/arch/qemu.h>
 

arch/x86/cpu/quark/dram.c

@@ -7,6 +7,7 @@
 #include <cpu_func.h>
 #include <errno.h>
 #include <fdtdec.h>
+#include <init.h>
 #include <malloc.h>
 #include <asm/mrccache.h>
 #include <asm/mtrr.h>

arch/x86/cpu/slimbootloader/sdram.c

@@ -4,6 +4,7 @@
  */
 
 #include <common.h>
+#include <init.h>
 #include <linux/sizes.h>
 #include <asm/e820.h>
 #include <asm/arch/slimbootloader.h>