96boards: Declare SPI0_CS pin as GPIO for Dragonboard410c

On the 96Boards Dragonboard410c, hardware controlled Chip Select
on the SPI0_CS pin is unreliable. So make it as a GPIO pin for
enabling the user to toggle it manually.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

src/arm/96boards.c

@@ -356,7 +356,13 @@ mraa_96boards()
     mraa_96boards_pininfo(b, 9, -1, 0, "UART0_RTS");
     mraa_96boards_pininfo(b, 10, -1, 0, "SPI0_DIN");
     mraa_96boards_pininfo(b, 11, -1, 0, "UART1_TXD");
-    mraa_96boards_pininfo(b, 12, -1, 0, "SPI0_CS");
+    // Only on Dragonboard410c, SPI0_CS pin is configured as GPIO for
+    // manual control since the HW Chip Select is not reliable
+    if (strncmp(b->platform_name, PLATFORM_NAME_DB410C, MAX_SIZE) == 0) {
+        mraa_96boards_pininfo(b, 12, 18, 1, "SPI0_CS", 0, 18);
+    } else {
+        mraa_96boards_pininfo(b, 12, -1, 0, "SPI0_CS");
+    }
     mraa_96boards_pininfo(b, 13, -1, 0, "UART1_RXD");
     mraa_96boards_pininfo(b, 14, -1, 0, "SPI0_DOUT");
     mraa_96boards_pininfo(b, 15, -1, 0, "I2C0_SCL");