Do not flush the cache in flush_cache_v(un)map for VIPT caches

In case of non-aliasing VIPT caches, there is no need to flush the whole
cache when new mapping is created. The patch introduces this condition
check. In the non-aliasing VIPT case flush_cache_vmap() needs a DSB
since the set_pte_at() function called from vmap_pte_range() does not
have such barrier (done usually via TLB flushing functions).

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>