clk: fixed-rate: Enable DM_FLAG_PRE_RELOC flag

fixed-rate driver is not different from clk_fixed_factor and it is required
very early in boot that's why setup flag for it.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/drivers/clk/clk_fixed_rate.c b/drivers/clk/clk_fixed_rate.c
index 2c20edd..55e1f8c 100644
--- a/drivers/clk/clk_fixed_rate.c
+++ b/drivers/clk/clk_fixed_rate.c
@@ -53,4 +53,5 @@
 	.ofdata_to_platdata = clk_fixed_rate_ofdata_to_platdata,
 	.platdata_auto_alloc_size = sizeof(struct clk_fixed_rate),
 	.ops = &clk_fixed_rate_ops,
+	.flags = DM_FLAG_PRE_RELOC,
 };