x86: generalize padding field handling

x86: generalize padding field handling

The original intention was to ignore padding fields, but the pattern
matched only ones whose names started with an underscore. Also match
fields whose names are in line with the C spec by not having a leading
underscore. (Note that the leading ^ in the sed regexps was pointless
and hence get dropped.)

This requires adjusting some vNUMA macros, to avoid triggering
"enumeration value ... not handled in switch" warnings, which - due to
-Werror - would cause the build to fail. (I have to admit that I find
these padding fields odd, when translation of the containing structure
is needed anyway.)

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>