arm: Add Aspeed machine

Aspeed devices are a common Baseboard Management Controller (BMC)
system on chip containing an ARM9 or ARM11 core, off-chip DDR RAM and
support for a large number of peripherals.

This patch adds basic support for the ast2400 and ast2500 machines,
capable of booting to a prompt in QEMU (-M palmetto-bmc), on an
Palmetto OpenPower development machine, and on the ast2500 EVB.

Signed-off-by: Joel Stanley <joel@jms.id.au>

arch/arm/mach-aspeed/Kconfig

@@ -0,0 +1,30 @@
+menuconfig ARCH_ASPEED
+	bool "Aspeed BMC architectures"
+	depends on ARCH_MULTI_V5 || ARCH_MULTI_V6
+	select SRAM
+	select WATCHDOG
+	select ASPEED_WATCHDOG
+	select MOXART_TIMER
+	help
+	  Say Y here if you want to run your kernel on an ASpeed BMC SoC.
+
+if ARCH_ASPEED
+
+config MACH_ASPEED_G4
+	bool "Aspeed SoC 4th Generation"
+	depends on ARCH_MULTI_V5
+	select CPU_ARM926T
+	help
+	 Say yes if you intend to run on an Aspeed ast2400 or similar
+	 fourth generation BMCs, such as those used by OpenPower Power8
+	 systems.
+
+config MACH_ASPEED_G5
+	bool "Aspeed SoC 5th Generation"
+	depends on ARCH_MULTI_V6
+	select CPU_V6
+	help
+	 Say yes if you intend to run on an Aspeed ast2500 or similar
+	 fifth generation Aspeed BMCs.
+
+endif