powerpc/spider-pci: Remove set but not used variable 'val'

Fixes gcc '-Wunused-but-set-variable' warning:
# WARNING: Fixes tag on line 3 doesn't match correct format
# WARNING: Fixes tag on line 3 doesn't match correct format
# WARNING: Fixes tag on line 3 doesn't match correct format
# WARNING: Fixes tag on line 3 doesn't match correct format
# WARNING: Fixes tag on line 3 doesn't match correct format
# WARNING: Fixes tag on line 3 doesn't match correct format

arch/powerpc/platforms/cell/spider-pci.c: In function 'spiderpci_io_flush':
arch/powerpc/platforms/cell/spider-pci.c:28:6: warning:
variable ‘val’ set but not used [-Wunused-but-set-variable]

It never used since introduction.
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210601085319.140461-1-libaokun1@huawei.com

arch/powerpc/platforms/cell/spider-pci.c

@@ -25,10 +25,9 @@ struct spiderpci_iowa_private {
 static void spiderpci_io_flush(struct iowa_bus *bus)
 {
 	struct spiderpci_iowa_private *priv;
-	u32 val;
 
 	priv = bus->private;
-	val = in_be32(priv->regs + SPIDER_PCI_DUMMY_READ);
+	in_be32(priv->regs + SPIDER_PCI_DUMMY_READ);
 	iosync();
 }