regulator: sy8827n: Fix W=1 build warning when CONFIG_OF=n

Fixing W=1 build warning when no support for device tree is there.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
Link: https://lore.kernel.org/r/20200810095753.59ce9f75@xhacker.debian


Signed-off-by: Mark Brown <broonie@kernel.org>