r200/r300/r600: remove dangling radeon_tex_getimage.c symlinks.

r200/r300/r600: remove dangling radeon_tex_getimage.c symlinks.

Commit d1fda903 (radeon: Drop mapping we were doing around
glGetTexImage()) removed the common Radeon source file
radeon_tex_getimage.c, and pulled it out of the r200, r300, r600, and
radeon makefiles.  But it left behind the symlinks that were being
used to share that file among the four directories.

This patch removes the dangling symlinks.

Reviewed-by: Brian Paul <brianp@vmware.com>