debugfs is another kernel virtual file system that should be mounted
if configured, so if it's configured into the kernel, mount it.
(From OE-Core rev: 55c4d3c55e4c3a7c2cda6d006cf7b78567bd3298)
Signed-off-by: Tom Zanussi <tom.zanussi@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>