ARM: 8404/1: dma-mapping: fix off-by-one error in bitmap size check

ARM: 8404/1: dma-mapping: fix off-by-one error in bitmap size check

nr_bitmaps member of mapping structure stores the number of already
allocated bitmaps and it is interpreted as loop iterator (it starts from
0 not from 1), so a comparison against number of possible bitmap
extensions should include this fact. This patch fixes this by changing
the extension failure condition. This issue has been introduced by
commit 4d852ef8c2544ce21ae41414099a7504c61164a0 ("arm: dma-mapping: Add
support to extend DMA IOMMU mappings").

Reported-by: Hyungwon Hwang <[email protected]>
Signed-off-by: Marek Szyprowski <[email protected]>
Reviewed-by: Hyungwon Hwang <[email protected]>
Cc: [email protected]  # v3.15+
Signed-off-by: Russell King <[email protected]>