qcacmn: Fix OOB in extract_reg_11d_new_country_event_tlv

In extract_reg_11d_new_country_event_tlv(), the
reg_11d_country_event->new_alpha2 buffer from the original WMI
message is copied into reg_11d_country->alpha2. Will only copy
REG_ALPHA2_LEN bytes into a buffer that REG_ALPHA2_LEN +1 bytes.
then reg_11d_country->alpha2 buffer is printed as a string.
Because the original reg_11d_new_country structure in
tgt_reg_11d_new_cc_handler() was allocated on the stack and
not initialized, there is no guarantee that the buffer is
NULL terminated. Due to this the WMI_LOGD() call will result in
an OOB issue when printing the buffer.

Change-Id: I20b0044974438d95e4c09f843db2a7f369c9b85d
CRs-Fixed: 2327718

wmi_unified_tlv.c

@@ -17854,6 +17854,7 @@ static QDF_STATUS extract_reg_11d_new_country_event_tlv(
 
 	qdf_mem_copy(reg_11d_country->alpha2,
 			&reg_11d_country_event->new_alpha2, REG_ALPHA2_LEN);
+	reg_11d_country->alpha2[REG_ALPHA2_LEN] = '\0';
 
 	WMI_LOGD("processed 11d country event, new cc %s",
 			reg_11d_country->alpha2);