Allocate enough memory for HAL_PIXL_FORMAT_YV12

Previously we were not allocating enough memory to align
the uv planes to 16 pixels.
We were allocating:
h * align(w,16) * 3 / 2 bytes
This should be:
h * align(w,16) + h * align(align(w,16)/2, 16)

Bug: 7431048
Change-Id: Iaba969795e8d20c29ee0b703af5dd884a4c88d2e
Signed-off-by: Rebecca Schultz Zavin <rebecca@android.com>