This is meant to test the sysfs entry for showing rc6 residency in
milliseconds. Remember, sysfs is a permanent interface.
v2: use new get_card interface to try "all" devices
check rc6p and rc6pp in addition to rc6
v3: rename rc6_residency.c to sysfs_rc6_residency.c
print better error messages
skip test if rc6 isn't enabled
v4: update to new sysfs names
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Ben Widawsky <benjamin.widawsky@intel.com>