[SCSI] mpt2sas: Fix security scan issues reported by source code analysis tool

Modified the source code as per the findings reported by the source
code analysis tool. Source code for the following functionalities
has been touched. None of the driver functionalities has changed.

- SMP Passthrough IOCTL
- Debug messages for MPT Replies (i.e. bit 9 of Logging Level)
- Task Management using sysfs
- Device removal, i.e. when a target device (including any PD within a volume)
  is removed, and Volume Deletion.
- Trace Buffer

Signed-off-by: Nagalakshmi Nandigama <nagalakshmi.nandigama@lsi.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>