[rdkb][common][hal][Refactor getRadioSupportedStandards for cmd buffer]

[Description]
Refactor getRadioSupportedStandards for cmd buffer.

[Release-log]
N/A

Change-Id: I900ade8a78ed15f746ace4f6a9be57fdf4a39328
diff --git a/src/wifi/wifi_hal.c b/src/wifi/wifi_hal.c
index 56983a8..02ec054 100644
--- a/src/wifi/wifi_hal.c
+++ b/src/wifi/wifi_hal.c
@@ -1781,7 +1781,7 @@
 //The output_string is a max length 64 octet string that is allocated by the RDKB code.  Implementations must ensure that strings are not longer than this.
 INT wifi_getRadioSupportedStandards(INT radioIndex, CHAR *output_string) //Tr181
 {
-    char cmd[128]={0};
+    char cmd[256]={0};
     char buf[128]={0};
     char temp_output[128] = {0};
     wifi_band band;