armbianmonitor: squash shellcheck warnings around the main getopts case statement

- `b` and `B` were never parsed
- an `*` case is added to handle invalid options

packages/bsp/common/usr/bin/armbianmonitor

@@ -124,7 +124,7 @@ Main() {
 } # Main
 
 ParseOptions() {
-	while getopts 'hHbBuUrRmMsnNd:Dc:C:pPvz' c; do
+	while getopts 'hHuUrRmMsnNd:Dc:C:pPvz' c; do
 		case ${c} in
 			H)
 				# display full help test
@@ -301,6 +301,10 @@ ParseOptions() {
 				Run7ZipBenchmark 2> /dev/null
 				exit 0
 				;;
+			*)
+				echo "Invalid flag: ${c}" >&2
+				exit 7
+				;;
 		esac
 	done
 } # ParseOptions