iommufd: Add config needed for iommufd_fail_nth

Add FAULT_INJECTION_DEBUG_FS and FAILSLAB configurations to the kconfig
fragment for the iommfd selftests. These kconfigs are needed by the
iommufd_fail_nth test.

Fixes: a9af47e ("iommufd/selftest: Test IOMMU_HWPT_GET_DIRTY_BITMAP")
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Muhammad Usama Anjum <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>

Author: musamaanjum

tools/testing/selftests/iommu/config

@@ -1,3 +1,5 @@
 CONFIG_IOMMUFD=y
+CONFIG_FAULT_INJECTION_DEBUG_FS=y
 CONFIG_FAULT_INJECTION=y
 CONFIG_IOMMUFD_TEST=y
+CONFIG_FAILSLAB=y