pinctrl: renesas: Annotate sentinels in tables

It does not make sense to have a comma after a sentinel, as any new
elements must be added before the sentinel. Hence drop all such commas.

Add comments to clarify the purpose of the empty elements.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/845f1d8285dd44522af1b0f429d4c6bd4759eb9e.1678272180.git.geert+renesas@glider.be

pinctrl: renesas: sh7722: Optimize fixed-width reserved fields

Describe registers with fixed-width register fields and many reserved
fields using the PINMUX_CFG_REG_VAR() macro, as the latter supports a
shorthand not requiring dummy values.

This reduces kernel size by 396 bytes.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/c3965b6f9ea603b185924136f859c6eca7d5d6f4.1649865241.git.geert+renesas@glider.be

pinctrl: renesas: Remove unneeded #include <linux/init.h>

The last __init annotations were removed from these source files almost
one decade ago.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/fb71c409ea3ad76163496e305dc955ca8e84416d.1649681741.git.geert+renesas@glider.be

pinctrl: renesas: Remove unneeded #include <linux/gpio.h>

Linus reports that some Renesas pin control sub-drivers are still
including <linux/gpio.h> instead of <linux/gpio/driver.h>. As these
sub-drivers don't need either, the includes can just be removed.

Reported-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/578825d779b45af745cc7623c7f69d2ddeadac4b.1645605227.git.geert+renesas@glider.be

pinctrl: Rename sh-pfc to renesas

The drivers/pinctrl/sh-pfc subdirectory was originally created to group
pin control drivers for various Renesas SuperH and SH-Mobile platforms.
However, the name "sh-pfc" no longer reflects its contents, as the
directory now contains pin control drivers for Renesas SuperH, ARM32,
and ARM64 SoCs.

Hence rename the subdirectory from drivers/pinctrl/sh-pfc to
drivers/pinctrl/renesas, and the related Kconfig symbol from
PINCTRL_SH_PFC to PINCTRL_RENESAS.

Rename the git branch in MAINTAINERS, too, for consistency.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20200909131534.12897-3-geert+renesas@glider.be