BSC_Tests: cosmetic: s/mr_conf_amr_5_90/c_mr_conf_5_90/

* This is a global constant, so prefix with 'c_' for consistency.
* The RSL_IE_MultirateCfg is all about AMR, remove redundant 'amr'.

Change-Id: I72405b7139fcfd0dbe90afc469ed4db71b43a87c
1 file changed