ARM: shmobile: sh7372 dtsi: Remove Legacy DTSI file

Remove the sh7372 DTSI file for the now unsupported sh7372 SoC.

Signed-off-by: Magnus Damm <damm+renesas@opensource.se>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>