MAINTAINERS: rectify entries for some i3c drivers after dt conversion

Commit 4bd69ec ("dt-bindings: i3c: Convert cdns,i3c-master to DT
schema") and commit 6742ca6 ("dt-bindings: i3c: Convert
snps,dw-i3c-master to DT schema") convert some i3c dt-bindings to yaml,
but miss to adjust its reference in MAINTAINERS.

Hence, ./scripts/get_maintainer.pl --self-test=patterns complains about
broken references.

Repair these file references in I3C DRIVER FOR CADENCE I3C MASTER IP and
I3C DRIVER FOR SYNOPSYS DESIGNWARE.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220601074212.19984-1-lukas.bulwahn@gmail.com

MAINTAINERS

@@ -9264,13 +9264,13 @@ F:	drivers/i2c/i2c-stub.c
 I3C DRIVER FOR CADENCE I3C MASTER IP
 M:	Przemysław Gaj <pgaj@cadence.com>
 S:	Maintained
-F:	Documentation/devicetree/bindings/i3c/cdns,i3c-master.txt
+F:	Documentation/devicetree/bindings/i3c/cdns,i3c-master.yaml
 F:	drivers/i3c/master/i3c-master-cdns.c
 
 I3C DRIVER FOR SYNOPSYS DESIGNWARE
 M:	Vitor Soares <vitor.soares@synopsys.com>
 S:	Maintained
-F:	Documentation/devicetree/bindings/i3c/snps,dw-i3c-master.txt
+F:	Documentation/devicetree/bindings/i3c/snps,dw-i3c-master.yaml
 F:	drivers/i3c/master/dw*
 
 I3C SUBSYSTEM