PCI: mobiveil: Fix infinite-loop in the INTx handling function

In the loop handling INTx interrupts in mobiveil_pcie_isr(), there is
no code to update the loop control variable, which is causing an
infinite loop.

Fix the code by reading the interrupt status registers inside the
loop.

Fixes: 9af6bcb1 ("PCI: mobiveil: Add Mobiveil PCIe Host Bridge IP driver")
Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Minghuan Lian <Minghuan.Lian@nxp.com>
Reviewed-by: Subrahmanya Lingappa <l.subrahmanya@mobiveil.co.in>
Acked-by: Karthikeyan Mitran <m.karthikeyan@mobiveil.co.in>
Tested-by: Karthikeyan Mitran <m.karthikeyan@mobiveil.co.in>

drivers/pci/controller/pcie-mobiveil.c

@@ -358,8 +358,9 @@ static void mobiveil_pcie_isr(struct irq_desc *desc)
 
 	/* Handle INTx */
 	if (intr_status & PAB_INTP_INTX_MASK) {
-		shifted_status = csr_readl(pcie, PAB_INTP_AMBA_MISC_STAT) >>
-					   PAB_INTX_START;
+		shifted_status = csr_readl(pcie, PAB_INTP_AMBA_MISC_STAT);
+		shifted_status &= PAB_INTP_INTX_MASK;
+		shifted_status >>= PAB_INTX_START;
 		do {
 			for_each_set_bit(bit, &shifted_status, PCI_NUM_INTX) {
 				virq = irq_find_mapping(pcie->intx_domain,
@@ -375,7 +376,12 @@ static void mobiveil_pcie_isr(struct irq_desc *desc)
 					   shifted_status << PAB_INTX_START,
 					   PAB_INTP_AMBA_MISC_STAT);
 			}
-		} while ((shifted_status >> PAB_INTX_START) != 0);
+
+			shifted_status = csr_readl(pcie,
+						   PAB_INTP_AMBA_MISC_STAT);
+			shifted_status &= PAB_INTP_INTX_MASK;
+			shifted_status >>= PAB_INTX_START;
+		} while (shifted_status != 0);
 	}
 
 	/* read extra MSI status register */