dropbear: change type of config option "Port" to scalar type "port"

it was never used anywhere, even LuCI works with "Port" as scalar type.

Signed-off-by: Konstantin Demin <[email protected]>

package/network/services/dropbear/files/dropbear.init

@@ -87,7 +87,7 @@ validate_section_dropbear()
 		'rsakeyfile:file' \
 		'keyfile:list(file)' \
 		'BannerFile:file' \
-		'Port:list(port):22' \
+		'Port:port:22' \
 		'SSHKeepAlive:uinteger:300' \
 		'IdleTimeout:uinteger:0' \
 		'MaxAuthTries:uinteger:3' \