wigig_sensing: change change_mode ioctl signature

The new definition separates error code report from burst_size. This
promotes uniformity in the ioctl definitions and prevents the usage of
errno.

Change-Id: I2145a8ba15cb25a82c1d1a4d4c3465e56f4358d6
Signed-off-by: Gidon Studinski <gidons@codeaurora.org>