mmc: core: Set cqe_enabled flag correctly

If cqe_enable wrapper returns error then cqe_enabled flag should be
false.
Set cqe_enabled flag only when there is no error from cqe_enable
wrapper.

Change-Id: I8a35454a7547f67f5836e4f8ddabd1e5910fd48a
Signed-off-by: Sarthak Garg <sartgarg@codeaurora.org>