platform: msm-shared: Always erase the whole partition when flashing UBI img

(Fix for "platform: msm-shared: Add UBI image awareness to fastboot code")

The original patch implemented an optimization that if the partition was found
to be erased while scaning, it wasnt re-erased before flashing. Cancel this
optimization since it may produce ECC errors.

Change-Id: I432f7277f17bdfccc3ae8a724ba210518850bea4
1 file changed