[binutils-gdb] Fix field size for TLSLE_MOVW_TPREL_* relocations.

[sergiodj+buildbot@redhat.com]

*** TEST RESULTS FOR COMMIT 07875fbce7911d7e6174d6398cec2872eb489613 ***

Author: Marcus Shawcroft <marcus.shawcroft@arm.com>
Branch: master
Commit: 07875fbce7911d7e6174d6398cec2872eb489613

Fix field size for TLSLE_MOVW_TPREL_* relocations.
The HOWTO table entries for the TLSLE_MOVW_TPREL_* relocations are
wrong by inspection.  The current implementation does not actually use
these field widths for these relocations but they should be corrected.