util/nvmutil: allow ./nvm gbe MAC

previously, if the user ran:

./nvm GBE [MAC address]

it would error, treating the MAC as a command

now if only 3 arguments are provided, and the
3rd argument ins't a valid command, it's treated
as a MAC address and validated accordingly.

this should make nvmutil easier to use, because
I imagine a lot of users forget to use setmac

there's no reason we should be so pedantic. we
should allow it to be used flexibly like this

Signed-off-by: Leah Rowe <leah@libreboot.org>

util/nvmutil/nvmutil.c

@@ -149,7 +149,10 @@ main(int argc, char *argv[])
 		cmd = cmd_setmac;
 	}
 
-	if (cmd == cmd_setmac) {
+	if ((cmd == NULL) && (argc > 2)) { /* nvm gbe [MAC] */
+		strMac = COMMAND;
+		cmd = cmd_setmac;
+	} else if (cmd == cmd_setmac) { /* nvm gbe setmac [MAC] */
 		strMac = strRMac; /* random MAC */
 		if (argc > 3) /* user-supplied MAC (can be random) */
 			strMac = MAC_ADDRESS;