SCSI: ARM: make fas216_dumpinfo function conditional

The fas216_dumpinfo function is only used by __fas216_checkmagic,
which is conditionally compiled, so we should put both functions
inside of the same #ifdef.

Without this patch, building rpc_defconfig results in:

drivers/scsi/arm/fas216.c:182:13: warning: 'fas216_dumpinfo' defined but not used [-Wunused-function]

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-scsi@vger.kernel.org