cpu: Add DM_FLAG_PRE_RELOC flag to various cpu drivers

It turns out commit c0434407b595 broke some boards which have DM CPU
driver with CONFIG_DISPLAY_CPUINFO option on. These boards just fail
to boot when print_cpuinfo() is called during boot.

Fixes: c0434407b595 ("board_f: Use static print_cpuinfo if CONFIG_CPU is active")
Reported-by: Stefan Roese <sr@denx.de>
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Stefan Roese <sr@denx.de>
Tested-by: Stefan Roese <sr@denx.de>
diff --git a/arch/x86/cpu/ivybridge/model_206ax.c b/arch/x86/cpu/ivybridge/model_206ax.c
index 33e5c62..6edc3e2 100644
--- a/arch/x86/cpu/ivybridge/model_206ax.c
+++ b/arch/x86/cpu/ivybridge/model_206ax.c
@@ -478,4 +478,5 @@
 	.bind		= cpu_x86_bind,
 	.probe		= cpu_x86_model_206ax_probe,
 	.ops		= &cpu_x86_model_206ax_ops,
+	.flags		= DM_FLAG_PRE_RELOC,
 };