target-arm: Move OMAP cp15_i_{max,min} reset to cpu_state_reset

Move the OMAP-specific cp15_i_{max,min} reset to cpu_state_reset;
since these registers are only accessible on CPUs with the
OMAPCP feature set there's no need to guard this reset with
either a CPUID or feature bit check.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Andreas Färber <afaerber@suse.de>
