qcacld-3.0: Fix NULL pointer dereferencing issues

Fix below issues:
1) check cds_get_context results before use
2) remove function calls from ASSERTs
3) make sure variables are initialized before use
4) check pointers for NULL before dereferencing

Change-Id: Iac92e6f2d1030a7dd12469e34341135bea7c781f
CRs-Fixed: 1047286
(cherry picked from commit a2547fd35fc517abfbc96363768b5d036d59d057)

core/bmi/src/ol_fw.c

@@ -289,7 +289,7 @@ __ol_transfer_bin_file(struct ol_context *ol_ctx, ATH_BIN_FILE file,
 #endif
 
 	if (file == ATH_BOARD_DATA_FILE) {
-		uint32_t board_ext_address;
+		uint32_t board_ext_address = 0;
 		int32_t board_ext_data_size;
 
 		temp_eeprom = qdf_mem_malloc(fw_entry_size);