ARM: Remove __flush_icache_all() from __flush_dcache_page()

Both call sites for __flush_dcache_page() end up calling
__flush_icache_all() themselves, so having __flush_dcache_page() do
this as well is wasteful.  Remove the duplicated icache flushing.

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