ARM: 6995/2: mm: remove unnecessary cache flush on v6 copypage

Originally introduced to maintain coherency between icache and dcache
in v6 nonaliasing mode. This is now handled by __sync_icache_dcache since
c0177800, therefore unnecessary in this function.

Signed-off-by: Heechul Yun <heechul@illinois.edu>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>