ARM: integrator: get rid of <mach/memory.h>

The Integrator has a custom <mach/memory.h> header defining the
BUS_OFFSET for *_to_bus and bus_to_* operations as offset from
0x80000000.

This switches the Integrator over to using the mechanism
introduced for the Keystone to provide the same offset using
the device tree, deletes <mach/memory.h> and augments the
Integrator device tree to provide the bus offset.

Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Jonathan Austin <jonathan.austin@arm.com>
Cc: Russell King <linux@arm.linux.org.uk>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

arch/arm/boot/dts/integratorap.dts

@@ -8,6 +8,7 @@
 / {
 	model = "ARM Integrator/AP";
 	compatible = "arm,integrator-ap";
+	dma-ranges = <0x80000000 0x0 0x80000000>;
 
 	aliases {
 		arm,timer-primary = &timer2;