pinctrl: freescale: remove generic pin config core support

pinctrl: freescale: remove generic pin config core support

No instance of "struct imx_pinctrl_soc_info" sets '.generic_pinconf =
true', so all of this is effectively dead code.

To make it easier to understand the actual code, remove all the unused
cruft. This effectively reverts a5cadbbb081c ("pinctrl: imx: add
generic pin config core support").

It was only in use by a single SOC (imx7ulp) for a few releases, and
the commit message of dbffda08f0e9 ("pinctrl: fsl: imx7ulp: change to
use imx legacy binding") suggests that it won't be used in the
future. Certainly no new user has appeared in 20+ releases, and should
the need arise, this can be dug out of git history again.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Fabio Estevam  <festevam@gmail.com>
Link: https://lore.kernel.org/r/20230302072132.1051590-1-linux@rasmusvillemoes.dk
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>