Include the new linux/kdebug.h instead of asm/kdebug.h.

Simply remove the asm/kdebug.h include if both had been included.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>