ARM: OMAP2+: Require proper GPMC timings for devices

Now that we have timings in the .dts files for smc91x
and 8250, we can remove the device specific checks and
just print out the bootloader timings for devices that
may not have timings in the .dts files.

Acked-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>