ARM: Only allow PM_SLEEP with CPUs which support suspend

Offering CONFIG_PM_SLEEP for CPUs which do not support suspend leads to
build errors, so only set CONFIG_ARCH_SUSPEND_POSSIBLE if we have a CPU
selected which supports suspend.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/Kconfig

@@ -2012,6 +2012,8 @@ source "kernel/power/Kconfig"
 
 config ARCH_SUSPEND_POSSIBLE
 	depends on !ARCH_S5P64X0 && !ARCH_S5P6442
+	depends on CPU_ARM920T || CPU_ARM926T || CPU_SA1100 || \
+		CPU_V6 || CPU_V6K || CPU_V7 || CPU_XSC3 || CPU_XSCALE
 	def_bool y
 
 endmenu