Revert "mmc: core: handle flush requests timeout"

* somehow causes random reboots when on 3g only

This reverts commit 2ec43f0da44d74e7adca62867fc2f8245a62e878.

Change-Id: Iff7e8e8b76e8ca12428175c1e882c5570aa27480
jflteatt: conform to the rest of jf devices

* fixes build issues with our consolidated defconfig

Change-Id: I514385e7ca3f1cbd884f7fc15c4426575da29fb0