msm8226-common: recovery: remove duplicate modem/firmware mount

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

Change-Id: Ibfe1cd62806620806fdf20ecde28c30bcdd90e7a
Merge "msm8226-common: recovery: remove duplicate modem/firmware mount" into cm-11.0