libstagefright: add default gralloc usage for detached surface

a surface can be managed by H/W GPU and
it will cause an error at H/W GPU due to
missing GRALLOC_USAGE_HW_TEXTURE usage.

Bug: 350667377
Test: atest android.mediav2.cts.CodecDecoderSurfaceTest

Change-Id: I9d7b46fb7ce3b22c2d82b4a3cbd797c9ea5feb69
Signed-off-by: Taehwan Kim <t_h.kim@samsung.com>