When bit is equal to 0x4, it means OPT_ZONE_DMA32 should be got from
GFP_ZONE_TABLE.  OPT_ZONE_DMA32 shall be equal to ZONE_DMA32 or
ZONE_NORMAL according to the status of CONFIG_ZONE_DMA32.

Similarly, when bit is equal to 0xc, that means OPT_ZONE_DMA32 should be
got with an allocation policy GFP_MOVABLE.  So ZONE_DMA32 or ZONE_NORMAL
is the possible result value.

Link: http://lkml.kernel.org/r/20180601163403.1032-1-yehs2007@zoho.comSigned-off-by: Huaisheng Ye <yehs1@lenovo.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>