pinctrl: Create subdirectory for StarFive drivers

Move the StarFive JH7100 pinctrl driver to a new subdirectory
in preparation for adding more StarFive pinctrl drivers. No
functional change.

Signed-off-by: Jianlong Huang <jianlong.huang@starfivetech.com>
Signed-off-by: Hal Feng <hal.feng@linux.starfivetech.com>
Link: https://lore.kernel.org/r/20220930060819.5320-1-hal.feng@linux.starfivetech.com


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>