ARM: configs: keystone: drop CONFIG_COMMON_CLK_DEBUG

this patch removes COMMON_CLK_DEBUG config option
from defconfig file as this config option is obsolete.

Signed-off-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>