x86: Disable KPROBES with DEBUG_RODATA for now

Right now Kprobes cannot write to the write protected kernel text when
DEBUG_RODATA is enabled. Disallow this in Kconfig for now.

Temporary fix for 2.6.22. In .23 add code to temporarily
unprotect it.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>