Currently, the tool's makefile override the tool's binary name
which is already been defined in the main makefile.
Hence fix is provided so that the tool's makefile get the tool's
binary name from the main makefile instead of overriding it.

Change-Id: I8af2bd391a96bba2dbcddef711338a94ebf5f038
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>