ARM: ux500: reform Ux500 family names

Counting the U9540 and the new U8540 as a U8500 family member
does not work. Instead, split the function in two:

cpu_is_u8500_family() covering U8500 and U8520
cpu_is_ux540_family() covering U9540 and U8540

This works much better in practice. Update users to keep the
same behaviour.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/arch/arm/mach-ux500/cpu-db8500.c b/arch/arm/mach-ux500/cpu-db8500.c
index db3c52d..2dd8593 100644
--- a/arch/arm/mach-ux500/cpu-db8500.c
+++ b/arch/arm/mach-ux500/cpu-db8500.c
@@ -80,7 +80,7 @@
 
 	iotable_init(u8500_common_io_desc, ARRAY_SIZE(u8500_common_io_desc));
 
-	if (cpu_is_u9540())
+	if (cpu_is_ux540_family())
 		iotable_init(u9540_io_desc, ARRAY_SIZE(u9540_io_desc));
 	else
 		iotable_init(u8500_io_desc, ARRAY_SIZE(u8500_io_desc));