msm8226-common: change usbdisk write permissions

Users are not able to write to /storage/usbdisk0
because they are not part of the media_rw (1023) group.
Removing the write restriction allows users to write to
usbdisk without root elevation.

Change-Id: I33177c167aa2e7a58b2a4bcae17e72c93ba7599a
msm8226-common: remove redundant init.mmi.radio.sh

init_falcon handles this.

Change-Id: I016b30a84530a65bcdbc942157d33a666972413e
msm8226-common: recovery: remove duplicate modem/firmware mount

/dev/block/platform/msm_sdcc.1/by-name/modem is
mounted to /firmware.

Change-Id: Ibfe1cd62806620806fdf20ecde28c30bcdd90e7a