cpufreq: imx: select CPU_FREQ_TABLE

CPUFreq driver of this platform uses APIs from freq_table.c and so must select
CPU_FREQ_TABLE.

Acked-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>