pinctrl: qcom: sdm670: Staticize groups and functions

The kernel test robot complains about undeclared local functions.
Fix it up.

Fixes: 9826035a75da ("pinctrl: qcom: add sdm670 lpi tlmm")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202604080950.Mvm8aN0a-lkp@intel.com/
Signed-off-by: Linus Walleij <linusw@kernel.org>