powerpc/32: Blacklist functions running with MMU disabled for kprobe

kprobe does not handle events happening in real mode, all
functions running with MMU disabled have to be blacklisted.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/3bf57066d05518644dee0840af69d36ab5086729.1585670437.git.christophe.leroy@c-s.fr

arch/powerpc/kernel/misc.S

@@ -36,6 +36,8 @@ _GLOBAL(add_reloc_offset)
 	add	r3,r3,r5
 	mtlr	r0
 	blr
+_ASM_NOKPROBE_SYMBOL(reloc_offset)
+_ASM_NOKPROBE_SYMBOL(add_reloc_offset)
 
 	.align	3
 2:	PPC_LONG 1b