MIPS: ath91: Remove pointless irqdisable/enable

The various interrupt flow handlers in ath79 are cascading interrupt
handlers. They all have a disable_irq_nosync()/enable_irq() pair
around the generic_handle_irq() call. The value of this disable/enable
is zero because its a complete noop:

disable_irq_nosync() merily increments the disable count without
actually masking the interrupt. enable_irq() soleley decrements the
disable count without touching the interrupt chip. The interrupt
cannot arrive again because the complete call chain runs with
interrupts disabled.

Remove it.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mips@linux-mips.org
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Patchwork: https://patchwork.linux-mips.org/patch/10703/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/ath79/irq.c

@@ -123,8 +123,6 @@ static void ar934x_ip2_irq_dispatch(unsigned int irq, struct irq_desc *desc)
 {
 	u32 status;
 
-	disable_irq_nosync(irq);
-
 	status = ath79_reset_rr(AR934X_RESET_REG_PCIE_WMAC_INT_STATUS);
 
 	if (status & AR934X_PCIE_WMAC_INT_PCIE_ALL) {
@@ -136,8 +134,6 @@ static void ar934x_ip2_irq_dispatch(unsigned int irq, struct irq_desc *desc)
 	} else {
 		spurious_interrupt();
 	}
-
-	enable_irq(irq);
 }
 
 static void ar934x_ip2_irq_init(void)
@@ -156,14 +152,12 @@ static void qca955x_ip2_irq_dispatch(unsigned int irq, struct irq_desc *desc)
 {
 	u32 status;
 
-	disable_irq_nosync(irq);
-
 	status = ath79_reset_rr(QCA955X_RESET_REG_EXT_INT_STATUS);
 	status &= QCA955X_EXT_INT_PCIE_RC1_ALL | QCA955X_EXT_INT_WMAC_ALL;
 
 	if (status == 0) {
 		spurious_interrupt();
-		goto enable;
+		return;
 	}
 
 	if (status & QCA955X_EXT_INT_PCIE_RC1_ALL) {
@@ -175,17 +169,12 @@ static void qca955x_ip2_irq_dispatch(unsigned int irq, struct irq_desc *desc)
 		/* TODO: flush DDR? */
 		generic_handle_irq(ATH79_IP2_IRQ(1));
 	}
-
-enable:
-	enable_irq(irq);
 }
 
 static void qca955x_ip3_irq_dispatch(unsigned int irq, struct irq_desc *desc)
 {
 	u32 status;
 
-	disable_irq_nosync(irq);
-
 	status = ath79_reset_rr(QCA955X_RESET_REG_EXT_INT_STATUS);
 	status &= QCA955X_EXT_INT_PCIE_RC2_ALL |
 		  QCA955X_EXT_INT_USB1 |
@@ -193,7 +182,7 @@ static void qca955x_ip3_irq_dispatch(unsigned int irq, struct irq_desc *desc)
 
 	if (status == 0) {
 		spurious_interrupt();
-		goto enable;
+		return;
 	}
 
 	if (status & QCA955X_EXT_INT_USB1) {
@@ -210,9 +199,6 @@ static void qca955x_ip3_irq_dispatch(unsigned int irq, struct irq_desc *desc)
 		/* TODO: flush DDR? */
 		generic_handle_irq(ATH79_IP3_IRQ(2));
 	}
-
-enable:
-	enable_irq(irq);
 }
 
 static void qca955x_irq_init(void)