iop: enable generic time

This updates the IOP platform to use the kernel's generic time
framework. With clockevent support in place, this reduces to
selecting GENERIC_TIME and removing the platform's private timer
->offset() operation (iop_gettimeoffset).

Tested on n2100, compile-tested for all plat-iop machines.

Signed-off-by: Mikael Pettersson <mikpe@it.uu.se>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index e732fcc..455284e 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -811,6 +811,7 @@
 config PLAT_IOP
 	bool
 	select GENERIC_CLOCKEVENTS
+	select GENERIC_TIME
 
 config PLAT_ORION
 	bool