beastpatcher: fix some minor issues

This mainly fixes some compiler warnings and makes it
work with mingw64.

Change-Id: Iabd13b5bed3427869ae78ceeb7e2255e68a6f7bd

utils/MTP/beastpatcher/Makefile

@@ -10,12 +10,12 @@ OUTPUT=beastpatcher.exe
 CROSS=
 else
 OUTPUT=beastpatcher
-CROSS=i586-mingw32msvc-
+CROSS=i686-w64-mingw32-
 endif
 endif
 
 ifneq ($(findstring MINGW,$(shell uname)),MINGW)
-LIBS := -lmtp -lusb
+LIBS := -lmtp
 ifdef STATIC
 LIBS := -Wl,-Bstatic $(LIBS) -Wl,-Bdynamic
 endif

utils/MTP/beastpatcher/mtp_libmtp.c

@@ -123,6 +123,8 @@ int mtp_send_firmware(struct mtp_info_t* mtp_info, unsigned char* fwbuf,
     size_t n;
     FILE* fwfile;
 
+    (void) ret; /* suppress a set but not used warning */
+
     /* Open a temporary file - this will be automatically deleted when closed */
     fwfile = tmpfile();