mm/hmm.c: suppress compilation warnings when CONFIG_HUGETLB_PAGE is not set

gcc reports that several variables are defined but not used.

For the first hunk CONFIG_HUGETLB_PAGE the entire if block is already
protected by pud_huge() which is forced to 0.  None of the stuff under the
ifdef causes compilation problems as it is already stubbed out in the
header files.

For the second hunk the dummy huge_page_shift macro doesn't touch the
argument, so just inline the argument.

Link: http://lkml.kernel.org/r/20190522195151.GA23955@ziepe.ca


Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>