cma_alloc() function doesn't really support gfp flags other than
__GFP_NOWARN, so convert gfp_mask parameter to boolean no_warn parameter.

This will help to avoid giving false feeling that this function supports
standard gfp flags and callers can pass __GFP_ZERO to get zeroed buffer,
what has already been an issue: see commit dd65a941f6ba ("arm64:
dma-mapping: clear buffers allocated with FORCE_CONTIGUOUS flag").

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>

---
 arch/powerpc/kvm/book3s_hv_builtin.c       | 2 +-
 drivers/s390/char/vmcp.c                   | 2 +-
 drivers/staging/android/ion/ion_cma_heap.c | 2 +-
 include/linux/cma.h                        | 2 +-
 kernel/dma/contiguous.c                    | 3 ++-
 mm/cma.c                                   | 8 ++++----
 mm/cma_debug.c                             | 2 +-
 7 files changed, 11 insertions(+), 10 deletions(-)