md/raid5: Drop unnecessary call to r5c_check_stripe_cache_usage()

Now that raid5_get_active_stripe() has been refactored it is appearant
that r5c_check_stripe_cache_usage() doesn't need to be called in
the wait_for_stripe branch.

r5c_check_stripe_cache_usage() will only conditionally call
r5l_wake_reclaim(), but that function is called two lines later.

Drop the call for cleanup.

Reported-by: Martin Oliveira <martin.oliveira@eideticom.com>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>