library/L1CTL_Types: add missing L1CTL_GPRS_RTS_IND message

This commit fixes the following warnings:

  While RAW-decoding type '@L1CTL_Types.L1ctlMessageLV':
    Invalid enum value '37' for '@L1CTL_Types.L1ctlMsgType':

Change-Id: I0772f5273ecc2fb0c3def1fd645828b216e3032f
Related: osmocom-bb.git I1494e0aac7555f6e01b4b435b77140afc42c098e
1 file changed