powerpc: Remove empty comment

Commit 2874c5fd ("treewide: Replace GPLv2 boilerplate/reference with
SPDX - rule 152") left an empty comment in machdep.h, as the boilerplate
was the only text in the comment. Remove the empty comment.
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190813051212.6387-1-jniethe5@gmail.com

arch/powerpc/include/asm/machdep.h

@@ -3,9 +3,6 @@
 #define _ASM_POWERPC_MACHDEP_H
 #ifdef __KERNEL__
 
-/*
- */
-
 #include <linux/seq_file.h>
 #include <linux/init.h>
 #include <linux/dma-mapping.h>