MAINTAINERS: remove the obsolete file entry for staging in ANDROID DRIVERS

MAINTAINERS: remove the obsolete file entry for staging in ANDROID DRIVERS

Commit 721412ed3d81 ("staging: remove ashmem") removes the last android
driver from staging, but misses to adjust MAINTAINERS.

Hence, ./scripts/get_maintainer.pl --self-test=patterns complains about a
broken reference.

Remove the obsolete file entry in ANDROID DRIVERS.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Link: https://lore.kernel.org/r/20220316124802.372-1-lukas.bulwahn@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>