nxp: ics307_clk: Guard get_board_ddr_clk function correctly

When we have CONFIG_DYNAMIC_DDR_CLK_FREQ set is the only time we should
have this function, so guard it so that we can include <clock_legacy.h>
in this file later on.

Signed-off-by: Tom Rini <trini@konsulko.com>
1 file changed