ARM: fix EFM32 build breakage caused by cpu_resume_arm

Fix:
arch/arm/kernel/sleep.S:121: Error: selected processor does not support ARM opcodes
arch/arm/kernel/sleep.S:123: Error: attempt to use an ARM instruction on a Thumb-only processor -- `adr r9,1f+1'
arch/arm/kernel/sleep.S:124: Error: attempt to use an ARM instruction on a Thumb-only processor -- `bx r9'

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>