MAINTAINERS: Add Kishon as maintainer of PHY bindings

DT bindings normally go in via subsystem maintainers, so add PHY
bindings under generic PHY framework.
Reported-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Cc: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: NRob Herring <robh@kernel.org>
Signed-off-by: NKishon Vijay Abraham I <kishon@ti.com>

MAINTAINERS

@@ -6189,6 +6189,7 @@ T:	git git://git.kernel.org/pub/scm/linux/kernel/git/kishon/linux-phy.git
 S:	Supported
 F:	drivers/phy/
 F:	include/linux/phy/
+F:	Documentation/devicetree/bindings/phy/
 
 GENERIC PINCTRL I2C DEMULTIPLEXER DRIVER
 M:	Wolfram Sang <wsa+renesas@sang-engineering.com>