ANDROID: gki_defconfig: Enable CONFIG_UDMABUF

The main use case is to allow very large O_DIRECT writes into a memfd,
which can then be converted into a udmabuf. (O_DIRECT writes into
regular dmabufs are not possible.)

Bug: 303531391
Bug: 389839576
Bug: 433225592
Change-Id: Ifd970826ed1ecb4fe2d365854bcd19276b07f614
Signed-off-by: T.J. Mercier <tjmercier@google.com>
(cherry picked from commit 2f84f21f)
Bug: 423003849
(cherry picked from commit e0a00524)