[SCSI] mpt fusion: make logging a global sysfs parameter

Wire up the mpt_debug_level module parameter so you can write to the
/sys/module/mptbase/parameters/mpt_debug_level and have it take effect
in every ioc.

Acked-by: "Moore, Eric" <Eric.Moore@lsi.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>