ARM: 6901/1: remove unneeded check of the cache_is_vipt_nonaliasing()

when cache_is_vipt_nonaliasing(), we always have pte_exec() true at
the end of this function, so no need for the additional check.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Saeed Bishara <saeed@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>