pinctrl: renesas: r8a7778: Remove unused PORT_GP_PUP_1() macro

The last user was removed in commit dd1f760b ("pinctrl: sh-pfc:
r8a7778: Use common PORT_GP_CFG_27() macro").

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Link: https://lore.kernel.org/r/129147ac57f5e931cc7108db0a6483b803a1b8f4.1619785375.git.geert+renesas@glider.be