scsi: ibmvscsi: Convert timers to use timer_setup()

In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to using the new timer_setup() and from_timer()
to pass the timer pointer explicitly.

Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "James E.J. Bottomley" <jejb@linux.vnet.ibm.com>
Cc: linux-scsi@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>