ARM: shmobile: Consolidate R8A7743 and R8A779[234] machine definitions

The four SoCs use identical machine operations, consolidate them into
two machine definitions in a single file.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Tested-by: Simon Horman <horms+renesas@verge.net.au>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>