powerpc/8xx: Erroneous double irq_eoi() on CPM IRQ in MPC8xx

irq_eoi() is already called by generic_handle_irq() so
it shall not be called a again
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NScott Wood <scottwood@freescale.com>

arch/powerpc/platforms/8xx/m8xx_setup.c

@@ -219,19 +219,12 @@ void mpc8xx_restart(char *cmd)
 
 static void cpm_cascade(unsigned int irq, struct irq_desc *desc)
 {
-	struct irq_chip *chip;
-	int cascade_irq;
-
-	if ((cascade_irq = cpm_get_irq()) >= 0) {
-		struct irq_desc *cdesc = irq_to_desc(cascade_irq);
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	int cascade_irq = cpm_get_irq();
 
+	if (cascade_irq >= 0)
 		generic_handle_irq(cascade_irq);
 
-		chip = irq_desc_get_chip(cdesc);
-		chip->irq_eoi(&cdesc->irq_data);
-	}
-
-	chip = irq_desc_get_chip(desc);
 	chip->irq_eoi(&desc->irq_data);
 }