[APM] Add shared version of APM emulation

Currently ARM and MIPS both have nearly identical copies of the APM
emulation code in their arch code.  Add yet another copy of it to
drivers char and make it selectable through SYS_SUPPORTS_APM_EMULATION.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
4 files changed