x86: drop pointless uses of __func__ / __FUNCTION__

x86: drop pointless uses of __func__ / __FUNCTION__

Non-debugging message text should be (and is in the cases here)
distinguishable without also logging function names. Debugging message
text, otoh, already includes file name and line number, so also
logging function names is redundant. One relatively pointless debugging
message gets removed altogether. In another case a missing log level
specifier gets added at once.

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