1-wire: add PDA TM7000 support

The PDA TM7000 is a 7-inch display panel with capacitive touch using
Atmel mxt1768E. It's solution is 800 x 480.

Signed-off-by: Bo Shen <voice.shen@atmel.com>
1-wire: correc the map table end indicator

Signed-off-by: Bo Shen <voice.shen@atmel.com>
1-wire: support for the schematic revision is numeric

If the schematic revision is numeric, it will report as default "A".
In order to report the correct revision, so, add support for the
schematic revision is numeric.

Signed-off-by: Bo Shen <voice.shen@atmel.com>