Commit
              34fa26c3996c6c63d40f59db3a5eb84a8c0348ad
              by laforgegsm/gsm_utils: Support the ER-GSM band (ARFCN 940..954)
So far we've supported R-GSM (ARFCN 955-974) and E-GSM (ARFCN 975..1023)
but not yet the ER-GSM range (ARFCN 940..954) in the gsm_arfcn2freq10()
and gsm_freq102arfcn() functions.  This patch fixes this.
Change-Id: I2f17bca405403ee12cfe7c5c804c135ab021b369