ARM: 7760/1: cpu_fa526_do_idle: remove WFI

As it was already suggested by Russell King and Arnd Bergmann:

https://lkml.org/lkml/2013/5/16/133

moxart and gemini seem to be the only platforms using CPU_FA526,
and instead of pointing arm_pm_idle to an empty function from
platform code, it makes sense to remove WFI code from the processor
specific idle function.

Applies to arm-soc/for-next (and 3.10-rc1).

Changes since v1:

1. remove WFI but make sure cpu_fa526_do_idle do not fall through
   to cpu_fa526_dcache_clean_area

Note: moxart boots and prints to UART without this patch, but input is broken.

Signed-off-by: Jonas Jensen <jonas.jensen@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>