partition: Perform BLKDISCARD on the block device before flashing image

Change-Id: Ifb13d47693edfc96369053199ac0b5d81910f104
diff --git a/partitions.hpp b/partitions.hpp
index 0a63d92..bdcea55 100755
--- a/partitions.hpp
+++ b/partitions.hpp
@@ -129,6 +129,7 @@
 	bool ReMount(bool Display_Error);                                         // Remounts the partition
 	bool ReMount_RW(bool Display_Error);                                      // Remounts the partition with read/write access
 	bool Bind_Mount(bool Display_Error);                                      // Bind mount partition if symlink mountpoint is populated
+	bool BlkDiscard();                                                        // Clear the partition using BLKDISCARD ioctl
 	bool Wipe(string New_File_System);                                        // Wipes the partition
 	bool Wipe();                                                              // Wipes the partition
 	bool Wipe_AndSec();                                                       // Wipes android secure