In kmap_atomic(), kmap_high_get() is invoked for checking already
mapped area. In __flush_dcache_page() and dma_cache_maint_page(),
we explicitly call kmap_high_get() before kmap_atomic()
when cache_is_vipt(), so kmap_high_get() can be invoked twice.
This is useless operation, so remove one.

v2: change cache_is_vipt() to cache_is_vipt_nonaliasing() in order to
be self-documented
Acked-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>