[SCSI] megaraid_sas: prints pending cmds before setting hw_crit_error

This patch adds function to print the pending frame details before returning
failure from the reset routine. It also exposes a new variable megasas_dbg_lvl
that allows the user to set the debug level for logging.

Signed-off-by: Sumant Patro <Sumant.Patro@lsil.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>