linux-user: Avoid conditional cpu_reset()

linux-user: Avoid conditional cpu_reset()

Some CPUs reset as part of cpu_init(), some others were reset
afterwards, some not at all. While some targets didn't implement a
cpu_[state_]reset() function, QOM cpu_reset() is always available.
There's nothing wrong with resetting twice on startup, so drop
the #ifdef.

Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Andreas Färber <afaerber@suse.de>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>