clk: at91: clk-sam9x60-pll: remove unused variable

Fix variable set but not used compilation warning.

Fixes: 43b1bb4a ("clk: at91: clk-sam9x60-pll: re-factor to support plls with multiple outputs")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/1598338751-20607-4-git-send-email-claudiu.beznea@microchip.com


Signed-off-by: Stephen Boyd <sboyd@kernel.org>