DM: crypto/fsl: Enable rsa DM driver usage before relocation

Enable rsa signature verification in SPL framework before relocation for
verification of main u-boot.

Reviewed-by: Aneesh Bansal <aneesh.bansal@nxp.com>
Signed-off-by: Sumit Garg <sumit.garg@nxp.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: York Sun <york.sun@nxp.com>

drivers/crypto/fsl/fsl_rsa.c

@@ -53,6 +53,7 @@ U_BOOT_DRIVER(fsl_rsa_mod_exp) = {
 	.name	= "fsl_rsa_mod_exp",
 	.id	= UCLASS_MOD_EXP,
 	.ops	= &fsl_mod_exp_ops,
+	.flags  = DM_FLAG_PRE_RELOC,
 };
 
 U_BOOT_DEVICE(fsl_rsa) = {