powerpc/32s: Make bat_addrs[] static

This table is used only locally. Declare it static.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/054fec0c139fc4c0a306360b360784733c0a6e65.1603348103.git.christophe.leroy@csgroup.eu