ANDROID: mm: lru_cache_disable skips lru cache drainnig

lru_cache_disable is not trivial cost since it should run work
from every cores in the system. Thus, repeated call of the
function whenever alloc_contig_range in the cma's allocation loop
is called is expensive.

This patch makes the lru_cache_disable smarter in that it will
not run __lru_add_drain_all since it knows the cache was already
disabled by someone else.
With that, user of alloc_contig_range can disable the lru cache
in advance in their context so that subsequent alloc_contig_range
for user's operation will avoid the costly function call.

Bug: 313795505
Change-Id: Icbb0e6dbf74644d45f562fd1d845888ca1f1f347
Signed-off-by: Richard Chang <richardycc@google.com>