i965: Make 'dw1' and 'bits' unnamed structures in brw_reg.

i965: Make 'dw1' and 'bits' unnamed structures in brw_reg.

Generated by

   sed -i -e 's/\.bits\././g' *.c *.h *.cpp
   sed -i -e 's/dw1\.//g' *.c *.h *.cpp

and then reverting changes to comments in gen7_blorp.cpp and
brw_fs_generator.cpp.

There wasn't any utility offered by forcing the programmer to list these
to access their fields. Removing them will reduce churn in future
commits.

This is C11 (and gcc has apparently supported it for sometime
"compatibility with other compilers")

See https://gcc.gnu.org/onlinedocs/gcc/Unnamed-Fields.html

Reviewed-by: Emil Velikov <emil.velikov@collabora.co.uk>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>