gallium: make all checks for PIPE_TEXTURE_2D check for PIPE_TEXTURE_RECT too

gallium: make all checks for PIPE_TEXTURE_2D check for PIPE_TEXTURE_RECT too

Searched for them with:
git grep -E '[!=]=.*PIPE_TEXTURE_2D|PIPE_TEXTURE_2D.*[!=]=|case.*PIPE_TEXTURE_2D'

Behavior hasn't been changed.