sh-pfc: Share common PORTCR macro definition

The macro is defined identically in four different locations. Share it.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Acked-by: Linus Walleij <linus.walleij@linaro.org>