Restore suppression of partition wiping in recovery

Even when using non-secure discard, partition wiping
can be unsafe in the following scenario:

-a complete rom is built with partition wiping enabled
 (there is no danger if only kernel and recovery are built)
-the full rom is installed on a device
-a different kernel is later installed or booted up
-the kernel is MMC_CAP_ERASE enabled (can trim)
-the kernel does not include the MAG2GA TRIM bug patch
-the device is affected by MAG2GA TRIM bug