arm: lpc32xx: add CONFIG_ARCH_LPC32XX build option

The explicit arch specific build symbol allows to group supported
boards, generalize common config options and it will serve as
a dependency for platform only drivers.

Two related board defconfigs are resynced after the change.

Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>

arch/arm/Kconfig

@@ -443,16 +443,6 @@ config ARCH_MVEBU
 	select SPI
 	imply CMD_DM
 
-config TARGET_DEVKIT3250
-	bool "Support devkit3250"
-	select CPU_ARM926EJS
-	select SUPPORT_SPL
-
-config TARGET_WORK_92105
-	bool "Support work_92105"
-	select CPU_ARM926EJS
-	select SUPPORT_SPL
-
 config TARGET_APF27
 	bool "Support apf27"
 	select CPU_ARM926EJS
@@ -668,6 +658,16 @@ config ARCH_MESON
 	  targeted at media players and tablet computers. We currently
 	  support the S905 (GXBaby) 64-bit SoC.
 
+config ARCH_LPC32XX
+	bool "NXP LPC32xx platform"
+	select CPU_ARM926EJS
+	select DM
+	select DM_GPIO
+	select DM_SERIAL
+	select SPL_DM if SPL
+	select SUPPORT_SPL
+	imply CMD_DM
+
 config ARCH_MX8M
 	bool "NXP i.MX8M platform"
 	select ARM64
@@ -1400,6 +1400,8 @@ source "arch/arm/mach-keystone/Kconfig"
 
 source "arch/arm/mach-kirkwood/Kconfig"
 
+source "arch/arm/cpu/arm926ejs/lpc32xx/Kconfig"
+
 source "arch/arm/mach-mvebu/Kconfig"
 
 source "arch/arm/cpu/armv7/ls102xa/Kconfig"
@@ -1518,11 +1520,9 @@ source "board/st/stv0991/Kconfig"
 source "board/tcl/sl50/Kconfig"
 source "board/ucRobotics/bubblegum_96/Kconfig"
 source "board/birdland/bav335x/Kconfig"
-source "board/timll/devkit3250/Kconfig"
 source "board/toradex/colibri_pxa270/Kconfig"
 source "board/vscom/baltos/Kconfig"
 source "board/woodburn/Kconfig"
-source "board/work-microwave/work_92105/Kconfig"
 source "board/xilinx/Kconfig"
 source "board/xilinx/zynq/Kconfig"
 source "board/xilinx/zynqmp/Kconfig"

arch/arm/cpu/arm926ejs/lpc32xx/Kconfig

@@ -0,0 +1,20 @@
+if ARCH_LPC32XX
+
+config SYS_SOC
+	default "lpc32xx"
+
+choice
+	prompt "NXP LPC32xx board select"
+
+config TARGET_DEVKIT3250
+	bool "Timll DevKit3250"
+
+config TARGET_WORK_92105
+	bool "Work Microwave Work_92105"
+
+endchoice
+
+source "board/timll/devkit3250/Kconfig"
+source "board/work-microwave/work_92105/Kconfig"
+
+endif