Like was done for the other non-upstream methods in
'struct ufs_hba_variant_ops', replace ->fill_prdt() with an Android
vendor hook. This is considered to be better because it avoids any
conflicts with upstream changes to 'struct ufs_hba_variant_ops'.
Note that as a side effect of this change, fill_prdt is no longer
allowed to sleep. That's fine for the only known use of this hook.
Bug: 162257402
Bug: 181359082
Change-Id: I8096932525c27b969193d769aff511a0114b35ad
Signed-off-by: Eric Biggers <ebiggers@google.com>