lockref: remove count argument of lockref_init

All users of lockref_init() now initialize the count to 1, so hardcode
that and remove the count argument.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Link: https://lore.kernel.org/r/20250130135624.1899988-4-agruenba@redhat.com


Signed-off-by: Christian Brauner <brauner@kernel.org>