powerpc/fsl_msi: reorganize structs to improve clarity and flexibility

Store cascade_data in an array inside the driver
data for later use.
Get rid of the msi_virq array since now we can
encapsulate the virqs in the cascade_data
directly and access them through the array
mentioned earlier.

Signed-off-by: Laurentiu Tudor <Laurentiu.Tudor@freescale.com>
Cc: Scott Wood <scottwood@freescale.com>
Cc: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
diff --git a/arch/powerpc/sysdev/fsl_msi.h b/arch/powerpc/sysdev/fsl_msi.h
index df9aa9f..420cfcb 100644
--- a/arch/powerpc/sysdev/fsl_msi.h
+++ b/arch/powerpc/sysdev/fsl_msi.h
@@ -27,6 +27,8 @@
 #define FSL_PIC_IP_IPIC   0x00000002
 #define FSL_PIC_IP_VMPIC  0x00000003
 
+struct fsl_msi_cascade_data;
+
 struct fsl_msi {
 	struct irq_domain *irqhost;
 
@@ -37,7 +39,7 @@
 	u32 srs_shift; /* Shift of the shared interrupt register select */
 	void __iomem *msi_regs;
 	u32 feature;
-	int msi_virqs[NR_MSI_REG_MAX];
+	struct fsl_msi_cascade_data *cascade_array[NR_MSI_REG_MAX];
 
 	struct msi_bitmap bitmap;