qcacmn: Use global OC table for lookup while updating RNR db

Operating class field used in RNR IE is of global operating
class. When getting frequency from RNR IE region specific
operating class is used for lookup instead of global.

Added changes to search operating class from global OC
table.

Change-Id: I200ab46187fed91cc66cd954b062c8d8ac44f631
CRs-Fixed: 3131600