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: NMichal Simek <michal.simek@xilinx.com>

drivers/clk/clk_fixed_rate.c

@@ -53,4 +53,5 @@ U_BOOT_DRIVER(clk_fixed_rate) = {
 	.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,
 };