egl/dri2: refactor dri2_query_surface, swrastGetDrawableInfo

egl/dri2: refactor dri2_query_surface, swrastGetDrawableInfo

Currently swrastGetDrawableInfo always initializes w and h, patch
refactors function as x11_get_drawable_info that returns success and
sets the values only if no error happened. Add swrastGetDrawableInfo
wrapper function as expected by DRI extension.

v2: init w,y,w,h in swrastGetDrawableInfo (Eric)

Signed-off-by: Tapani Pälli <tapani.palli@intel.com>
Reported-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>