[SCSI] mpt fusion: Request I/O resources only when required

This patch modifies the I/O resource allocation behavior of FUSION
driver.  The current version of driver allocates the I/O resources
even if they are not required and this creates trouble in low resource
environments.  This driver now uses
pci_enable_device_mem/pci_enable_device functions to differentiate the
resource allocations.

Signed-off-by: Sathya Prakash <sathya.prakash@lsi.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
diff --git a/drivers/message/fusion/mptbase.h b/drivers/message/fusion/mptbase.h
index b49b706..d83ea96 100644
--- a/drivers/message/fusion/mptbase.h
+++ b/drivers/message/fusion/mptbase.h
@@ -629,6 +629,7 @@
 	dma_addr_t		HostPageBuffer_dma;
 	int			 mtrr_reg;
 	struct pci_dev		*pcidev;	/* struct pci_dev pointer */
+	int			bars;		/* bitmask of BAR's that must be configured */
 	u8			__iomem *memmap;	/* mmap address */
 	struct Scsi_Host	*sh;		/* Scsi Host pointer */
 	SpiCfgData		spi_data;	/* Scsi config. data */