uwb.h: fix implicit use of asm/page.h for PAGE_SIZE

Once we clean up the implicit presence of module.h (and all its
sub-includes), we'll see an implicit dependency on page.h for
the PAGE_SIZE define. So fix it in advance.

Signed-off-by: Paul Gortmaker <[e-mail]>

include/linux/uwb.h

···
 #include <linux/wait.h>
 #include <linux/workqueue.h>
 #include <linux/uwb/spec.h>
+#include <asm/page.h>
 
 struct uwb_dev;
 struct uwb_beca_e;