Fix a scribbler in the PMS driver.

The ESGL bit was left uninitialized when executing the REPORT LUNS
ioctl. This could allow a zeroed data buffer to be treated as a
scatter/gather list. The firmware would eventually walk past the end
of the data buffer, potentially find what looked like a valid
address/length pair, and write the result to semi-random memory.

Obtained from:	Dell EMC Isilon
MFC after:	1 week
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D19398

sys/dev/pms/RefTisa/tisa/sassata/sas/ini/itdio.c

@@ -1874,7 +1874,9 @@ tiNumOfLunIOCTLreq(
       
     agSSPFrame->dataLength = REPORT_LUN_LEN;
     agSSPFrame->agSgl.len =	sizeof(agsaSSPCmdInfoUnit_t);
-    
+    agSSPFrame->agSgl.extReserved = 0;
+    CLEAR_ESGL_EXTEND(agSSPFrame->agSgl.extReserved);
+
     status = saSSPStart(agRoot, agIORequest, 0, agDevHandle, agRequestType,agSASRequestBody,agNULL,
     										   &ossaSSPIoctlCompleted);
     if(status != AGSA_RC_SUCCESS)