powerpc: address missing-prototypes warnings

There are a few warnings in powerpc64 defconfig builds after -Wmissing-prototypes
gets promoted from W=1 to the default warning set:

arch/powerpc/mm/book3s64/pgtable.c:422:6: error: no previous prototype for 'arch_report_meminfo' [-Werror=missing-prototypes]
arch/powerpc/platforms/cell/ras.c:275:5: error: no previous prototype for 'cbe_sysreset_hack' [-Werror=missing-prototypes]
arch/powerpc/platforms/cell/spu_manage.c:29:21: error: no previous prototype for 'spu_devnode' [-Werror=missing-prototypes]
arch/powerpc/platforms/pasemi/time.c:12:17: error: no previous prototype for 'pas_get_boot_time' [-Werror=missing-prototypes]
arch/powerpc/platforms/powermac/feature.c:1532:13: error: no previous prototype for 'g5_phy_disable_cpu1' [-Werror=missing-prototypes]
arch/powerpc/platforms/86xx/pic.c:28:13: error: no previous prototype for 'mpc86xx_init_irq' [-Werror=missing-prototypes]
drivers/pci/pci-sysfs.c:936:13: error: no previous prototype for 'pci_adjust_legacy_attr' [-Werror=missing-prototypes]

Address these by including the right header files or marking the
functions static. The audit.c one is a bit tricky since compat_audit.h
cannot include regular kernel headers tht have conflicting types on
32-bit powerpc.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
[mpe: Drop change to __vmemmap_free() which only exists in mm]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230727122720.2558065-1-arnd@kernel.org