dt-bindings: timer: renesas, cmt: Document r8a7744 CMT support

Document SoC specific compatible strings for r8a7744. No driver change
is needed as the fallback strings will activate the right code.

Signed-off-by: Biju Das <biju.das@bp.renesas.com>
Reviewed-by: Chris Paterson <Chris.Paterson2@renesas.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/timer/renesas,cmt.txt

@@ -24,6 +24,8 @@ Required Properties:
     - "renesas,r8a73a4-cmt1" for the 48-bit CMT1 device included in r8a73a4.
     - "renesas,r8a7743-cmt0" for the 32-bit CMT0 device included in r8a7743.
     - "renesas,r8a7743-cmt1" for the 48-bit CMT1 device included in r8a7743.
+    - "renesas,r8a7744-cmt0" for the 32-bit CMT0 device included in r8a7744.
+    - "renesas,r8a7744-cmt1" for the 48-bit CMT1 device included in r8a7744.
     - "renesas,r8a7745-cmt0" for the 32-bit CMT0 device included in r8a7745.
     - "renesas,r8a7745-cmt1" for the 48-bit CMT1 device included in r8a7745.
     - "renesas,r8a7790-cmt0" for the 32-bit CMT0 device included in r8a7790.