sh: minor fixes

This patch contains the following fixes:
- Adds sh7785 support to CONFIG_EARLY_SCIF_CONSOLE_PORT.
- Removes duplicate include from rts7751r2d irq code.
- Removes CONFIG_CPU_HAS_INTC from sh7720 Kconfig entry.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>