imx: add i.MX8 SoCs OTP SIP(silicon provider) service support

For NXP's i.MX8 SoCs with system controller inside, OTP is
maintained by SCFW, Linux needs to call SMC to trap to TF-A
for OTP read/write etc. operations by calling SCFW API.

This patch adds OTP SIP service support.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
diff --git a/plat/imx/common/imx_sip_handler.c b/plat/imx/common/imx_sip_handler.c
index 2e50cf3..a096a06 100644
--- a/plat/imx/common/imx_sip_handler.c
+++ b/plat/imx/common/imx_sip_handler.c
@@ -102,3 +102,29 @@
 
 	return SMC_OK;
 }
+
+int imx_otp_handler(uint32_t smc_fid,
+		void *handle,
+		u_register_t x1,
+		u_register_t x2)
+{
+	int ret;
+	uint32_t fuse;
+
+	switch (smc_fid) {
+	case IMX_SIP_OTP_READ:
+		ret = sc_misc_otp_fuse_read(ipc_handle, x1, &fuse);
+		SMC_RET2(handle, ret, fuse);
+		break;
+	case IMX_SIP_OTP_WRITE:
+		ret = sc_misc_otp_fuse_write(ipc_handle, x1, x2);
+		SMC_RET1(handle, ret);
+		break;
+	default:
+		ret = SMC_UNK;
+		SMC_RET1(handle, ret);
+		break;
+	}
+
+	return ret;
+}