dmaengine: idxd: Fix the error handling path in idxd_cdev_register()

If a call to alloc_chrdev_region() fails, the already allocated resources
are leaking.

Add the needed error handling path to fix the leak.

Fixes: 42d279f9 ("dmaengine: idxd: add char driver to expose submission portal to userland")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/1b5033dcc87b5f2a953c413f0306e883e6114542.1650521591.git.christophe.jaillet@wanadoo.fr


Signed-off-by: Vinod Koul <vkoul@kernel.org>