x86: cpumask: use work_on_cpu in arch/x86/kernel/microcode_core.c
x86: cpumask: use work_on_cpu in arch/x86/kernel/microcode_core.c

Impact: don't play with current's cpumask

Straightforward indirection through work_on_cpu().  One change is
that the error code from microcode_update_cpu() is now actually
plumbed back to microcode_init_cpu(), so now we printk if it fails
on cpu hotplug.

Signed-off-by: Rusty Russell <df9728c9e5104131c08c7adb03af425394842596@rustcorp.com.au>
Cc: Andrew Morton <5c1e68b099950c134891f0b6e179498a8ebe9cf9@linux-foundation.org>
Cc: Dmitry Adamushko <e662e14f6c703a049579d1bead8e040b40a3d5b5@gmail.com>
Cc: Peter Oruba <9bb2e390ac8d70bf0b71b64798d60e425898e4e7@amd.com>
LKML-Reference: <200903111632.37279.df9728c9e5104131c08c7adb03af425394842596@rustcorp.com.au>
Signed-off-by: Ingo Molnar <9dbbbf0688fedc85ad4da37637f1a64b8c718ee2@elte.hu>

KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas