n64: cleanup n64cart_probe()

The goto label fail_queue is needed to cleanup the queue allocation
when devm_platform_ioremap_resource() or alloc_disk() fails, either of
these two functions are not dependent on the queue variable which is
allocated prior to these calls.

Allocate the queue variable after successful alloc_disk(). Return
error directly when devm_platform_ioremap_resource() or alloc_disk()
fail. Remove fail_queue label and a call to the blk_cleanup_queue().

Direct return from these two functions allows us to remove the local
variable err and allocating queue after alloc_disk() allows us to
remove the local variable queue so we use disk->queue directly.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Lauri Kasanen <cand@gmx.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>