dload_util: Add normal dload mode entrance

Enum determines if the requested dload mode is emergency or normal.
All dependent function calls are updated respectively.
msm8974 and msm8226 set_download_mode() functions are updated with the
target-specific normal download mode address

Change-Id: I500c1e3c7e835ad6a6fa59ea2701790a7fd12769
diff --git a/app/aboot/aboot.c b/app/aboot/aboot.c
index 7c7f78b..59f43dd 100644
--- a/app/aboot/aboot.c
+++ b/app/aboot/aboot.c
@@ -1977,15 +1977,15 @@
 	/* Check if we should do something other than booting up */
 	if (keys_get_state(KEY_VOLUMEUP) && keys_get_state(KEY_VOLUMEDOWN))
 	{
-		dprintf(ALWAYS,"dload mode key sequence detected");
-		if (set_download_mode())
+		dprintf(ALWAYS,"dload mode key sequence detected\n");
+		if (set_download_mode(EMERGENCY_DLOAD))
 		{
-			dprintf(CRITICAL,"dload mode not supported by target");
+			dprintf(CRITICAL,"dload mode not supported by target\n");
 		}
 		else
 		{
 			reboot_device(0);
-			dprintf(CRITICAL,"Failed to reboot into dload mode");
+			dprintf(CRITICAL,"Failed to reboot into dload mode\n");
 		}
 		boot_into_fastboot = true;
 	}