[otp_ctrl] Add draft hjson for otp controller

Signed-off-by: Michael Schaffner <msf@opentitan.org>
diff --git a/hw/Makefile b/hw/Makefile
index 266a247..f86b0de 100644
--- a/hw/Makefile
+++ b/hw/Makefile
@@ -14,6 +14,7 @@
        hmac          \
        i2c           \
        nmi_gen       \
+       otp_ctrl      \
        padctrl       \
        pinmux        \
        pwrmgr        \