kconfig warns when PINCTRL_SINGLE is selected but PINCTRL is not
set, so also set PINCTRL for ARCH_DAVINCI. This prevents a
kconfig/build warning:

   WARNING: unmet direct dependencies detected for PINCTRL_SINGLE
     Depends on [n]: PINCTRL [=n] && OF [=y] && HAS_IOMEM [=y]
     Selected by [y]:
     - ARCH_DAVINCI [=y] && ARCH_MULTI_V5 [=y]

Closes: lore.kernel.org/r/202311070548.0f6XfBrh-lkp@intel.com

Fixes: f962396c ("ARM: davinci: support multiplatform build for ARM v5")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Bartosz Golaszewski <brgl@bgdev.pl>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linux-arm-kernel@lists.infradead.org
Cc: patches@armlinux.org.uk
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>