x86/ucode: Drop the sanity check for interrupts being disabled

x86/ucode: Drop the sanity check for interrupts being disabled

Of the substantial number of things which can go wrong during microcode load,
this is not one.  Loading occurs entirely within the boundary of a single
WRMSR instruction.  Its certainly not a BUG()-worthy condition.

Xen has legitimate reasons to not want interrupts enabled at this point, but
that is to do with organising the system rendezvous.  As these are private low
level helpers invoked only from the microcode core logic, forgo the check
entirely.

While dropping system.h, clean up the processor.h include which was an
oversight in the previous header cleanup.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>