msm: cpufreq: Check cpufreq_frequency_table NULL

This is required during single kernel binary support where one target
supports cpufreq and other target is at the initial stages of bringup.
Since we cannot remove CONFIG_CPU_FREQ_MSM from the config file, but
still support the boot on both of them adding a check for targets where
table is not initialized by the acpu clock driver.

Change-Id: I5f52c246586f0c0378a1b2873a064ef69601e3c6
Signed-off-by: Taniya Das <tdas@codeaurora.org>