LU-5612 osd: typo in osd_declare_write()

LU-5612 osd: typo in osd_declare_write()

Some bits are lost when porting the fix of LU-4611
3902ff4c54925b2f1fcb732a32ed7ee5428e9f77

That could result in insufficient credits in certain situation.

Signed-off-by: Niu Yawei <yawei.niu@intel.com>
Change-Id: I828a75c674978278b5adaf210586baa177ea0dc9
Reviewed-on: http://review.whamcloud.com/11889
Tested-by: Jenkins
Reviewed-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>