Fix Thumb2 bl range options.

Fix Thumb2 bl range options.

2009-12-21  Ramana Radhakrishnan  <ramana.radhakrishnan@arm.com>
            Richard Earnshaw  <richard.earnshaw@arm.com>

        * config/tc-arm.c (encode_thumb2_b_bl_offset): New. Refactored
        from md_apply_fix.
        (md_apply_fix): Fixup range checks for Thumb2 version
        of unconditional calls. Call encode_thumb2_b_bl_offset for
        unconditional branches / function calls.