soc: samsung: pmu: Remove unused and duplicated defines

The exynos-regs-pmu.h was never a complete list of PMU registers.  It
contained a lot of holes for registers which were not used.  However, a
lot of unused defines came along with porting the code from vendor
kernel.  Few of defines were also duplicated.

Remove them so the file will be slightly smaller.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>