ndtest: fix typo class_regster -> class_register

Fixes: dd6cad2 ("testing: nvdimm: make struct class structures constant")
Signed-off-by: Yi Zhang <yi.zhang@redhat.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/20231127040026.362729-1-yi.zhang@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: yizhanglinux

tools/testing/nvdimm/test/ndtest.c

@@ -924,7 +924,7 @@ static __init int ndtest_init(void)
 
 	nfit_test_setup(ndtest_resource_lookup, NULL);
 
-	rc = class_regster(&ndtest_dimm_class);
+	rc = class_register(&ndtest_dimm_class);
 	if (rc)
 		goto err_register;