ANDROID: dm-user: no_llseek() is about to go away

As per upstream commit cb787f4ac0 ("[tree-wide] finally take
no_llseek out"), .llseek should not be assigned to no_llseek anymore,
and the latter is gone.

It has been #define'd to NULL for a long time, so it's safe to
proactively remove it now, avoiding build breakage when GKI merges that
upstream commit.

Fixes: cb787f4ac0 ("[tree-wide] finally take no_llseek out")
Test: TH
Bug: 367265496
Bug: 370896014
Change-Id: Ie02f4c1b863dc9786d3c205a0835a9d1a52e11e0
Signed-off-by: André Draszik <draszik@google.com>
Signed-off-by: Matthias Maennich <maennich@google.com>

drivers/md/dm-user.c

@@ -1014,7 +1014,6 @@ static int dev_release(struct inode *inode, struct file *file)
 static const struct file_operations file_operations = {
 	.owner = THIS_MODULE,
 	.open = dev_open,
-	.llseek = no_llseek,
 	.read_iter = dev_read,
 	.write_iter = dev_write,
 	.release = dev_release,