orangefs: simplify orangefs_inode_getattr interface

No need to store the received mask.  It is either STATX_BASIC_STATS or
STATX_BASIC_STATS & ~STATX_SIZE.  If STATX_SIZE is requested, the cache
is bypassed anyway, so the cached mask is unnecessary to decide whether
to do a real getattr.

This is a change.  Previously a getattr would want size and use the
cached size.  All of the in-kernel callers that wanted size did not want
a cached size.  Now a getattr cannot use the cached size if it wants
size at all.

Signed-off-by: Martin Brandenburg <martin@omnibond.com>
Signed-off-by: Mike Marshall <hubcap@omnibond.com>