memzero.h: Remove no-op assignment

memset(3) returns the input pointer.  The assignment was effectively a
no-op, and just confused the code.

Cc: Christian Göttsche <cgzones@googlemail.com>
Cc: Serge Hallyn <serge@hallyn.com>
Cc: Iker Pedrosa <ipedrosa@redhat.com>
Signed-off-by: Alejandro Colomar <alx@kernel.org>

lib/memzero.h

@@ -28,7 +28,7 @@ memzero(void *ptr, size_t size)
 #elif defined(HAVE_EXPLICIT_BZERO)
 	explicit_bzero(ptr, size);
 #else
-	ptr = memset(ptr, '\0', size);
+	memset(ptr, '\0', size);
 	__asm__ __volatile__ ("" : : "r"(ptr) : "memory");
 #endif
 }