Revert "serial: sh-sci: Remove SCIx_RZ_SCIFA_REGTYPE"

This reverts commit 7acece71

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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>