add jiff_sysfs driver
test-jiff.sh: fix tab/space usage
add foo_sysfs driver
foo_sysfs: remove unnecessary mutexes

Remove unnecessary mutexes for sysfs show/store functions.  Locking is
done on the buffer used internally by show/store and does not need to be
done again.
test-id.sh: echo $DEV to show device being used
consistent #include ordering
id_jiff_foo_sysfs: synchronized error handling to foo

Synchronize the error handling code in foo init to those in id and
jiffies.  This will produce fewer differences when building the
id_jiff_foo_sysfs driver.
id_jiff_foo_sysfs: start id_jiff_foo_sysfs driver with id driver

Create id_jiff_foo_sysfs driver by starting from id driver.
id_jiff_foo_sysfs: add jiffies functionality

Include jiff_sysfs driver functionality in to id_jiff_foo_sysfs driver.
id_jiff_foo_sysfs: include foo functionality

Include foo_sysfs driver functionality in to id_jiff_foo_sysfs driver.
id_jiff_foo: add $DEV output to test-foo.sh