HID: Read calibration data from external sensor

Adding IOCTLs to give userspace control over to start / stop
IMU streaming and read calibration data from the external
device.

Change-Id: Iee5103e3a13cc31e4afcac13284e3594f49735bf
Signed-off-by: Rohit Bandi <rohitbandi@codeaurora.org>
Signed-off-by: Sathish Ambley <sathishambley@codeaurora.org>