e_comp_wl_subsurface: Do not resize the below_obj for optimizing gpu memory

e_comp_wl_subsurface: Do not resize the below_obj for optimizing gpu memory

before this patch, the below_obj is resized according to size of object of ec.
in normal scenario, the below_obj does not use extra gpu memory.
but the below object use extra gpu memory when evas_map is applied to
the below_obj.
(size of extra gpu memory is same size of the below obj)
this patch is for optimizing gpu memory.
the below_obj is resized by 1x1 when it is created and evas_map is applied
with size of object of ec.
it makes the below obj always use extra gpu memory for 1x1 size.

Change-Id: Ied098c06b0cd153bc1218155ae385c2848a9d4be