x86/microcode: Don't return error if microcode update is not needed

x86/microcode: Don't return error if microcode update is not needed

Commit 347b54683 ("x86/microcode: Synchronize late microcode loading")
incorrectly returns -EINVAL error on all request_microcode_fw() failures
in reload_store(). In fact, when update is not needed or if there is no
microcode to load we don't need to treat this as an error.

Orabug: 29759756

Fixes: 347b54683 ("x86/microcode: Synchronize late microcode loading")
Reported-by: Jamie Iles <jamie.iles@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
Reviewed-by: Jamie Iles <jamie.iles@oracle.com>
Reviewed-by: Mihai Carabas <mihai.carabas@oracle.com>
Reviewed-by: Bhavesh Davda <bhavesh.davda@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: John Haxby <john.haxby@oracle.com>
Signed-off-by: Brian Maly <brian.maly@oracle.com>