[SCSI] qla2xxx: Allow the extended-error-logging flag to be dynamic.

The module parameter, ql2xextended_error_logging, can now be
set dynamically by writing to the following sysfs entry:

	/sys/module/qla2xxx/parameters/ql2xextended_error_logging

This alleviates the need for the driver to be unloaded and
reloaded in order to enable logging.

Signed-off-by: Andrew Vasquez <andrew.vasquez@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>