MAINTAINERS: Add entries for Renesas RZ/G2L MTU3a counter driver

Add the MAINTAINERS entries for the Renesas RZ/G2L MTU3a counter
driver.
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/20230330111632.169434-6-biju.das.jz@bp.renesas.com

MAINTAINERS

@@ -17847,6 +17847,14 @@ S:	Supported
 F:	Documentation/devicetree/bindings/iio/adc/renesas,rzg2l-adc.yaml
 F:	drivers/iio/adc/rzg2l_adc.c
 
+RENESAS RZ/G2L MTU3a COUNTER DRIVER
+M:	Biju Das <biju.das.jz@bp.renesas.com>
+L:	linux-iio@vger.kernel.org
+L:	linux-renesas-soc@vger.kernel.org
+S:	Supported
+F:	Documentation/devicetree/bindings/timer/renesas,rz-mtu3.yaml
+F:	drivers/counter/rz-mtu3-cnt.c
+
 RENESAS RZ/N1 A5PSW SWITCH DRIVER
 M:	Clément Léger <clement.leger@bootlin.com>
 L:	linux-renesas-soc@vger.kernel.org