ARM: EXYNOS: Remove regs-pmu.h header dependency from pm_domain

Current "pm_domain.c" file uses "S5P_INT_LOCAL_PWR_EN" definition from
"regs-pmu.h" and hence needs to include this header file. As there is
no other user of "S5P_INT_LOCAL_PWR_EN" definition other than pm_domain,
to remove "regs-pmu.h" header file dependency from "pm_domain.c"  it's
better we define this definition in "pm_domain.c" file itself and thus it
will help in removing header file inclusion from "pm_domain.c".
Also removing "S5P_" prefix from macro.

Signed-off-by: Pankaj Dubey <pankaj.dubey@samsung.com>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>