ARM: prefetch: remove redundant "cc" clobber

The pld instruction does not affect the condition flags, so don't bother
clobbering them.

Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
ARM: prefetch: add support for prefetchw using pldw on SMP ARMv7+ CPUs

SMP ARMv7 CPUs implement the pldw instruction, which allows them to
prefetch data cachelines in an exclusive state.

This patch defines the prefetchw macro using pldw for CPUs that support
it.

Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>