powerpc/mm: remove unused function prototype

Commit f384796c ("powerpc/mm: Add support for handling > 512TB address
in SLB miss") removed function slb_miss_bad_addr(struct pt_regs *regs), but
kept its declaration in the prototype file. This patch simply removes the
function definition.
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/include/asm/asm-prototypes.h

@@ -61,7 +61,6 @@ void RunModeException(struct pt_regs *regs);
 void single_step_exception(struct pt_regs *regs);
 void program_check_exception(struct pt_regs *regs);
 void alignment_exception(struct pt_regs *regs);
-void slb_miss_bad_addr(struct pt_regs *regs);
 void StackOverflow(struct pt_regs *regs);
 void kernel_fp_unavailable_exception(struct pt_regs *regs);
 void altivec_unavailable_exception(struct pt_regs *regs);