Make tlbcam_addrs[] static.

Declare TLBCAM[] in mm/mmu_decl.h

And use NULL instead of 0 as pointer when calling restore_to_as0().
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/fd0cc30b5556428ce1d8a1fc0f983b462e88a956.1647200488.git.christophe.leroy@csgroup.eu