Fill in function to convert GPIO pin to a number

Convert the pin, like "A7" to the number that identifies
that GPIO in /sys/class/gpio/.

This most likely only supports ASPEED BMCs, though of course
support can be added for others if the need arises and this
code is still in use.

Change-Id: I404716652ffc29c27933ed13225bc074341fa473
Signed-off-by: Matt Spinler <spinler@us.ibm.com>
1 file changed