v4l2: Fix some mistakes about NV12_8L128
Fix a typo that miss a break in the switch statement. The typo is intoduced by !1379 (merged)
And the format NV12_8L128 is missed in gst_v4l2_object_get_caps_info. I'm not sure how this mistake is happened. But sorry for these mistake.
Edited by ming qian