MAINTAINERS: update marvell,armada-3700-utmi-phy.yaml reference

Changeset 6569d838 ("dt-bindings: phy: convert phy-mvebu-utmi to YAML schema")
renamed: Documentation/devicetree/bindings/phy/phy-mvebu-utmi.txt
to: Documentation/devicetree/bindings/phy/marvell,armada-3700-utmi-phy.yaml.

Update its cross-reference accordingly.

Fixes: 6569d838 ("dt-bindings: phy: convert phy-mvebu-utmi to YAML schema")
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/9342a88ed44726a1cc405470c834d746d4d0524c.1622648507.git.mchehab+huawei@kernel.orgSigned-off-by: Vinod Koul <vkoul@kernel.org>

MAINTAINERS

@@ -10888,7 +10888,7 @@ MARVELL ARMADA 3700 PHY DRIVERS
 M:	Miquel Raynal <miquel.raynal@bootlin.com>
 S:	Maintained
 F:	Documentation/devicetree/bindings/phy/phy-mvebu-comphy.txt
-F:	Documentation/devicetree/bindings/phy/phy-mvebu-utmi.txt
+F:	Documentation/devicetree/bindings/phy/marvell,armada-3700-utmi-phy.yaml
 F:	drivers/phy/marvell/phy-mvebu-a3700-comphy.c
 F:	drivers/phy/marvell/phy-mvebu-a3700-utmi.c