clk: Loongson1: Remove usage of CLK_IS_BASIC

This flag doesn't look to be used by any code, just set in the clk init
structure and then never tested again. Remove it from this driver as it
doesn't provide any benefit. Also remove parenthesis nearby that are not
needed and include clk.h to fix a sparse warning about static function
definition.

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