serial-dmm: Use dummy info struct for rs9lcd parser

serial-dmm: Use dummy info struct for rs9lcd parser

The rs9lcd parser, which is used for the RadioShack 22-812 does not use its
*info parameter, and therefore did not have a rs9lcd_info struct declared.

With recent re-factoring of the receive data callbacks, it became necessary to
pass a struct pointer. This made the RECV_DATA macro look like:

- RECV_DATA(RADIOSHACK_22_812, metex14)

giving the wrong impression that the RadioShack 22-182 uses the
metex14 protocol, which is not the case.

Create a dummy rs9lcd_info struct, and correctly identify the parser
as rs9lcd in the RECV_DATA macro:

+ RECV_DATA(RADIOSHACK_22_812, rs9lcd)

Signed-off-by: Alexandru Gagniuc <redacted>