x86/HPET: mask interrupt while changing affinity

x86/HPET: mask interrupt while changing affinity

While being unable to reproduce the "No irq handler for vector ..."
messages observed on other systems, the change done by 5dc3fd2 ('x86:
extend diagnostics for "No irq handler for vector" messages') appears
to point at the lack of masking - at least I can't see what else might
be wrong with the HPET MSI code that could trigger these warnings.

While at it, also adjust the message printed by aforementioned commit
to not pointlessly insert spaces - we don't need aligned tabular output
here.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>