cpufreq: OMAP driver depends CPUfreq tables

The OMAP driver depends on CPUfreq table support for creating a table
of frequencies from the OPP layer.  Ensure that it's build to avoid
link-time errors.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
[khilman@ti.com: make user-selectable, but default y]
Signed-off-by: Kevin Hilman <khilman@ti.com>