Return error immediately if set_console_mode is not supported

Currently, if set_console_mode is not supported by the driver, the
error is recorded on the node.last_error field, but the user is not
otherwise notified.  This field should only be used for asynchronous
feedback; the determination as to whether set_console_mode is supported is
synchronous. Therefor, it should return an error to the user immediately
and not alter node.last_error.

Closes-bug: #1312757
Change-Id: I015047175161809258ec08a02b2490613cf94466
Merge "Return error immediately if set_console_mode is not supported"