mmc: sdhci-msm: force 32bit ADMA descriptors

SDCC AXI master uses 32-bit addressing so there's no need to use
64-bit descriptors. Using 32-bit descriptors instead will reduce
the memory footprint.
This change masks the 64-bit capability to force 32-bit ADMA
descriptors.

CRs-Fixed: 719303
Change-Id: Ifb8095763136bbc795227bdfcb346d1e1fae42c7
Signed-off-by: Gilad Broner <gbroner@codeaurora.org>