Merge pull request ARMmbed#73 from soramame21/ren-disco-f429

Support SD card driver on DISCO_F429ZI

Author: Deepika

config/mbed_lib.json

@@ -81,6 +81,12 @@
              "SPI_CLK":  "PC_10",
              "SPI_CS":   "PA_15"
          },
+         "DISCO_F429ZI": {
+            "SPI_MOSI": "PC_12",
+            "SPI_MISO": "PC_11",
+            "SPI_CLK":  "PC_10",
+            "SPI_CS":   "PA_15"
+        },
         "NUCLEO_L031K6": {
              "SPI_MOSI": "SPI_MOSI",
              "SPI_MISO": "SPI_MISO",