__machine_check_early_realmode_p*() are currently declared as extern
in cputable.c and because of this when compiled with "C=1" (which
enables semantic checker) produces these warnings.

    CHECK   arch/powerpc/kernel/mce_power.c
  arch/powerpc/kernel/mce_power.c:709:6: warning: symbol '__machine_check_early_realmode_p7' was not declared. Should it be static?
  arch/powerpc/kernel/mce_power.c:717:6: warning: symbol '__machine_check_early_realmode_p8' was not declared. Should it be static?
  arch/powerpc/kernel/mce_power.c:722:6: warning: symbol '__machine_check_early_realmode_p9' was not declared. Should it be static?
  arch/powerpc/kernel/mce_power.c:740:6: warning: symbol '__machine_check_early_realmode_p10' was not declared. Should it be static?

Patch here moves the declaration to asm/mce.h and includes the same in
cputable.c

Fixes: ae744f34 ("powerpc/book3s: Flush SLB/TLBs if we get SLB/TLB machine check errors on power8")
Fixes: 7b9f71f9 ("powerpc/64s: POWER9 machine check handler")
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200817005618.3305028-1-maddy@linux.ibm.com