In commit 1bba0dc9

 cpu_reset()
was renamed to cpu_state_reset(), to allow introducing a new cpu_reset()
that would operate on QOM objects.

All callers have been updated except for one in target-mips, so drop all
implementations except for the one in target-mips and move the
declaration there until MIPSCPU reset can be fully QOM'ified.

Signed-off-by: Andreas Färber <afaerber@suse.de>
Acked-by: Michael Walle <michael@walle.cc> (for lm32)
Acked-by: Max Filippov <jcmvbkbc@gmail.com> (for xtensa)
Acked-by: Edgar E. Iglesias <edgar.iglesias@gmail.com> (for mb + cris)
Acked-by: Alexander Graf <agraf@suse.de> (for ppc)
Acked-by: Blue Swirl <blauwirbel@gmail.com>