mmc: core: change test of auto_bkops configured

Changing the test of whether auto_bkops is configured
allows for a case where the host tried to configure
auto_bkops yet the CMD6 failed in configuring the
device. This allows a case where manual bkops is configured
on a eMMC 5.1 device

Change-Id: Ia6c411f516bf27b8a5865109dcf4b290eb3d8e46
Signed-off-by: Dov Levenglick <dovl@codeaurora.org>