riscv: ccache: Remove unused variable

Reading the count register clears the interrupt signal. Currently, the
count registers are read into 'regval' variable but the variable is
never used. Therefore remove it. V2 of this patch add comments to
justify the readl calls without checking the return value.
Signed-off-by: NYash Shah <yash.shah@sifive.com>
Signed-off-by: NPaul Walmsley <paul.walmsley@sifive.com>

arch/riscv/mm/sifive_l2_cache.c

@@ -109,13 +109,14 @@ EXPORT_SYMBOL_GPL(unregister_sifive_l2_error_notifier);
 
 static irqreturn_t l2_int_handler(int irq, void *device)
 {
-	unsigned int regval, add_h, add_l;
+	unsigned int add_h, add_l;
 
 	if (irq == g_irq[DIR_CORR]) {
 		add_h = readl(l2_base + SIFIVE_L2_DIRECCFIX_HIGH);
 		add_l = readl(l2_base + SIFIVE_L2_DIRECCFIX_LOW);
 		pr_err("L2CACHE: DirError @ 0x%08X.%08X\n", add_h, add_l);
-		regval = readl(l2_base + SIFIVE_L2_DIRECCFIX_COUNT);
+		/* Reading this register clears the DirError interrupt sig */
+		readl(l2_base + SIFIVE_L2_DIRECCFIX_COUNT);
 		atomic_notifier_call_chain(&l2_err_chain, SIFIVE_L2_ERR_TYPE_CE,
 					   "DirECCFix");
 	}
@@ -123,7 +124,8 @@ static irqreturn_t l2_int_handler(int irq, void *device)
 		add_h = readl(l2_base + SIFIVE_L2_DATECCFIX_HIGH);
 		add_l = readl(l2_base + SIFIVE_L2_DATECCFIX_LOW);
 		pr_err("L2CACHE: DataError @ 0x%08X.%08X\n", add_h, add_l);
-		regval = readl(l2_base + SIFIVE_L2_DATECCFIX_COUNT);
+		/* Reading this register clears the DataError interrupt sig */
+		readl(l2_base + SIFIVE_L2_DATECCFIX_COUNT);
 		atomic_notifier_call_chain(&l2_err_chain, SIFIVE_L2_ERR_TYPE_CE,
 					   "DatECCFix");
 	}
@@ -131,7 +133,8 @@ static irqreturn_t l2_int_handler(int irq, void *device)
 		add_h = readl(l2_base + SIFIVE_L2_DATECCFAIL_HIGH);
 		add_l = readl(l2_base + SIFIVE_L2_DATECCFAIL_LOW);
 		pr_err("L2CACHE: DataFail @ 0x%08X.%08X\n", add_h, add_l);
-		regval = readl(l2_base + SIFIVE_L2_DATECCFAIL_COUNT);
+		/* Reading this register clears the DataFail interrupt sig */
+		readl(l2_base + SIFIVE_L2_DATECCFAIL_COUNT);
 		atomic_notifier_call_chain(&l2_err_chain, SIFIVE_L2_ERR_TYPE_UE,
 					   "DatECCFail");
 	}