power: Fix unmet dependency on POWER_SUPPLY by POWER_RESET by uncoupling them

Currently the reset/power off handlers (POWER_RESET) and Adaptive Voltage
Scaling class (POWER_AVS) are not built when POWER_SUPPLY is disabled.
The POWER_RESET is also not visible in drivers main section of config.

However they do not really depend on power supply so they can be built
always. The objects for power supply drivers already depend on
particular Kconfig symbols so there is no need for any changes in
drivers/power/Makefile.

This allows selecting POWER_RESET from main drivers config section and
fixes following build warning (encountered on ARM exynos defconfig when
POWER_SUPPLY is disabled manually):

warning: (ARCH_HISI && ARCH_INTEGRATOR && ARCH_EXYNOS && ARCH_VEXPRESS && REALVIEW_DT) selects POWER_RESET which has unmet direct dependencies (POWER_SUPPLY)
warning: (ARCH_EXYNOS) selects POWER_RESET_SYSCON which has unmet direct dependencies (POWER_SUPPLY && POWER_RESET && OF)
warning: (ARCH_EXYNOS) selects POWER_RESET_SYSCON_POWEROFF which has unmet direct dependencies (POWER_SUPPLY && POWER_RESET && OF)

Reported-by: Pavel Fedin <p.fedin@samsung.com>
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>