clk: xilinx: Drop duplicate depends on COMMON_CLK

This entire Kconfig file is only included within the if COMMON_CLK
section of the drivers/clk/Kconfig file. That makes the depends on
COMMON_CLK here redundant. Remove it.

Cc: Shubhrajyoti Datta <shubhrajyoti.datta@amd.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lore.kernel.org/r/20221003203103.2705007-1-sboyd@kernel.org