mmc: mvebu: Remove unused MMC_CAP.. macros

Removed MMC_CAP_NONREMOVABLE, MMC_CAP_NEEDS_POLL macros from
mvebu_mmc.h to avoid redefining of these macros when compiled with
mvebu based configs.

Signed-off-by: T Karthik Reddy <t.karthik.reddy@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>