checkpatch: add XA_STATE and XA_STATE_ORDER to the macro declaration list

XA_STATE() and XA_STATE_ORDER macro uses are declarations.

Add them to the declaration macro list to avoid suggesting a blank line
after declarations when used.

Link: https://lkml.kernel.org/r/144314f4bf2c58cf2336028a75a5127e848abd81.camel@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Reported-by: David Howells <dhowells@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>