mptfusion: fix msgContext in mptctl_hp_hostinfo

Hi,

without this patch the istwiRWRequest->MsgContext is always set to zero,
this patch saves the MsgContext in a msgcontext variable and then restores
the value.
Thanks to  David Jeffery who found the issue and did the analysis.

Signed-off-by: Tomas Henzl <thenzl@redhat.com>
Acked-by: Desai, Kashyap <Kashyap.Desai@lsi.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/message/fusion/mptctl.c

@@ -2432,9 +2432,9 @@ mptctl_hp_hostinfo(unsigned long arg, unsigned int data_size)
 	int			rc, cim_rev;
 	ToolboxIstwiReadWriteRequest_t	*IstwiRWRequest;
 	MPT_FRAME_HDR		*mf = NULL;
-	MPIHeader_t		*mpi_hdr;
 	unsigned long		timeleft;
 	int			retval;
+	u32			msgcontext;
 
 	/* Reset long to int. Should affect IA64 and SPARC only
 	 */
@@ -2581,11 +2581,11 @@ mptctl_hp_hostinfo(unsigned long arg, unsigned int data_size)
 	}
 
 	IstwiRWRequest = (ToolboxIstwiReadWriteRequest_t *)mf;
-	mpi_hdr = (MPIHeader_t *) mf;
+	msgcontext = IstwiRWRequest->MsgContext;
 	memset(IstwiRWRequest,0,sizeof(ToolboxIstwiReadWriteRequest_t));
+	IstwiRWRequest->MsgContext = msgcontext;
 	IstwiRWRequest->Function = MPI_FUNCTION_TOOLBOX;
 	IstwiRWRequest->Tool = MPI_TOOLBOX_ISTWI_READ_WRITE_TOOL;
-	IstwiRWRequest->MsgContext = mpi_hdr->MsgContext;
 	IstwiRWRequest->Flags = MPI_TB_ISTWI_FLAGS_READ;
 	IstwiRWRequest->NumAddressBytes = 0x01;
 	IstwiRWRequest->DataLength = cpu_to_le16(0x04);