net: mvpp2: simplify mvpp2_bm_bufs_add()

The mvpp2_bm_bufs_add() currently creates a fake cookie by calling
mvpp2_bm_cookie_pool_set(), just to be able to call
mvpp2_pool_refill(). But all what mvpp2_pool_refill() does is extract
the pool ID from the cookie, and call mvpp2_bm_pool_put() with this ID.

Instead of doing this convoluted thing, just call mvpp2_bm_pool_put()
directly, since we have the BM pool ID.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>