staging: comedi: pcmad: fix analog input data on pcmad12
staging: comedi: pcmad: fix analog input data on pcmad12

According to the PCM-A/D-12/16 Operations Manual:

NOTE: On the PCM-A/D-12 the lower nibble of the hex value will always be 0.

Fix the pcmad_ai_insn_read() function to properly handle this by shifting
the data after it has been read.

Signed-off-by: H Hartley Sweeten <382ff55d8e07d1082d179e669636cd1552da4f36@visionengravers.com>
Cc: Ian Abbott <9e6ba6483b6a3e14d61f7c987e72ecb5b46122d6@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <4645f7897fd33786a2ee1264d590b3c400559d85@linuxfoundation.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs