We already have it limited by the ID_PART_ENTRY_NAME, it is very less
likely that someone will have sdcard with the partition names which are
similar to modem partition.
This fixes rmtfs for @MartijnBraam who for some reason have internal mmc
as mmcblk1 and not 0.
Add modem-qcom-msm-downstream-common package that pulls in the
dependencies.
qcom_rmtfs now has udev rules to find the storage partitions. My hope
is they can be written flexibly enough to cover all devices and kernel
flavors.