Revert "serial: sh-sci: Remove SCIx_RZ_SCIFA_REGTYPE"

This reverts commit 7acece71.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Chris Brandt <chris.brandt@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>