fstab.common: Fix mmc sdcard path for 6.x and newer kernel versions am: f988e76cb7 am: 02333b37c3 am: 5b7305c77c

Original change: https://android-review.googlesource.com/c/device/linaro/dragonboard/+/2868694

Change-Id: I323703676ef65d487bbe00fae9b1cdae0f38d2ff
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>