OMAP3: Fix a cpu type check problem

cpu_is_omap3517() and cpu_is_omap3505() are the subgroups of cpu_is_omap34xx(),
so we should check cpu_is_omap3517() and cpu_is_omap3505() first, then check
cpu_is_omap34xx().

Otherwise, All AM35XX (Sitara) clocks do not get registered and device drivers
(ti_hecc, etc...) that depend on those clocks are failing to get the clock and
end up with non working device.

Signed-off-by: Stanley.Miao <stanley.miao@windriver.com>
Tested-by: Igor Grinberg <grinberg@compulab.co.il>
Signed-off-by: Tony Lindgren <tony@atomide.com>