linux-user: bsd-user: Don't reset X86CPU twice

Since commit 65dee38052597b6285eb208125369f01b29ba6c1 (target-i386:
move cpu_reset and reset callback to cpu.c) the x86 CPU is reset through
cpu_init() but was still reset immediately after in linux-user and
bsd-user. Clean this up.

Similarly in linux-user/syscall.c it is also reset after cpu_copy().
But that's a bug of its own, fixing which poses a semantic change.

Signed-off-by: Andreas Färber <afaerber@suse.de>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>