Making INTRNG a requirement on armv6

[Andrew Turner]

Hello arm,

I would like to make INTRNG a requirement on armv6. This is to help
with moving more armv6 kernel configurations into GENERIC. It also
helps when we want a child interrupt controller, e.g. a GPIO driver.

Most of the current armv6 kernel configurations already use INTRNG, so
only a few places need to be updated. 

I’ve run a test build making it an error to not have INTRNG enabled and
found the following armv6 configs fail:

AML8726
ARMADAXP
DIGI-CCWMX53
EFIKA_MX
IMX53
IMX53-QSB
VERSATILEPB
YYHD18

I'm interested in people who have this hardware to try enabling INTRNG
and testing. Note that this may require the interrupt controller driver
the SoC uses to be ported to INTRNG.

Andrew