bldrmsg: Only emmc /misc is supported

Change-Id: Ic0716557a87ec0638e2dbed1c3f743231e8b2f8e
diff --git a/bootloader_message/bootloader_message.cpp b/bootloader_message/bootloader_message.cpp
index 362d9cb..4d1ce5b 100644
--- a/bootloader_message/bootloader_message.cpp
+++ b/bootloader_message/bootloader_message.cpp
@@ -39,7 +39,7 @@
 
 static std::string misc_blkdev;
 
-void set_misc_device(const char* type, const char* name) {
+void set_misc_device(std::string name) {
     misc_blkdev = name;
 }