pinctrl: PINCTRL_AMDISP should depend on DRM_AMD_ISP

The AMD Image Signal Processor GPIO pin control functionality is only
present on AMD platforms with ISP support, and its platform device is
instantiated by the AMD ISP driver.  Hence add a dependency on
DRM_AMD_ISP, to prevent asking the user about this driver when
configuring a kernel that does not support the AMD ISP.

Fixes: e97435ab ("pinctrl: amd: isp411: Add amdisp GPIO pinctrl")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/3685561e8e3cd1d94bce220eeb6001d659da615c.1742306024.git.geert+renesas@glider.be


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