96boards: Use consistent pin numbering on 96boards platforms

Every 96Boards baseboard uses the same expansion connector, but the
current 96Boards initialization code assigns the SoC specific GPIO
numbers instead of being consistent across all boards. Change the code
to assign 96Boards GPIO-A through GPIO-L to MRAA GPIOs 23-34.

v2: Create info for all the LS connector pins, not just the GPIO pins.
    This gives us room to describe other pins in the future.

Signed-off-by: Grant Likely <grant.likely@linaro.org>
Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
Srinivas Kandagatla <srinivas.kandagatla@linaro.org>

include/arm/96boards.h

@@ -37,9 +37,7 @@ extern "C" {
 #define MRAA_96BOARDS_LS_I2C_COUNT  2
 #define MRAA_96BOARDS_LS_SPI_COUNT  1
 #define MRAA_96BOARDS_LS_UART_COUNT 2
-
-#define DB410C_PINCOUNT	122
-#define HIKEY_PINCOUNT	512
+#define MRAA_96BOARDS_LS_PIN_COUNT  40
 
 mraa_board_t* mraa_96boards();