dingdong: enable RW firmware signature verification

Check RSA signature of the RW firmware and jump to it if it is valid.

Signed-off-by: Todd Broch <tbroch@chromium.org>

BRANCH=none
BUG=chrome-os-partner:31193
TEST=flash on dingdong and boot with both bad and good RW firmware and
see it jump to RW only on the latter.

Change-Id: Ife8d1f9bcc16d796b9005a9761610119e456dd63
Reviewed-on: https://chromium-review.googlesource.com/231830
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
Reviewed-by: Alec Berg <alecaberg@chromium.org>
Reviewed-by: Todd Broch <tbroch@chromium.org>
Commit-Queue: Todd Broch <tbroch@chromium.org>
Tested-by: Todd Broch <tbroch@chromium.org>

board/dingdong/board.h

@@ -19,6 +19,9 @@
 #define CONFIG_ADC
 #define CONFIG_BOARD_PRE_INIT
 #define CONFIG_HW_CRC
+#define CONFIG_RSA
+#define CONFIG_RWSIG
+#define CONFIG_SHA256
 #define CONFIG_USB
 #define CONFIG_USB_BOS
 #define CONFIG_USB_INHIBIT_CONNECT

board/dingdong/dev_key.pem

@@ -0,0 +1,27 @@
+-----BEGIN RSA PRIVATE KEY-----
+MIIEpAIBAAKCAQEAqhcIe02T0+guB+QDIKTy578gwH0W0BpZM4B0scTq0ozQ6YJe
+9O74HBWYlWUkbx+/AaM50yeroqx6DC4ZLgm8PcBFpCkxhuOdP6BZbjEqEoI4nVOg
+nDsW3XpNODYueA7IpqiOjUgAcAeNTEfdxIGGh6XWwsJmGdbJCWu4SiWsKyJVThCr
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+z7vZQaelxsFrzHPgY2amX1uruSI4BaZ8aGYTtKzcTkzSnT/jD8QTiDnSYsMXs7h4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+dL6PtiJcOGeFodL12Sz1QRZVksMfpxz0XaVpxPsCgYAmDDi58f1VM/qL8kItYlXB
+7ka7EMbUIVMMuiPVUY6jupSHgYNFXrOWpa4OVlYBfGfpy+XzyL9THtGAw12szZU+
+kIuf152hB6FE6OB3DxS8NiJhiCyqMvPQx85/5tkruPZg7sWSVZouICrsCUAPVJ0x
+1pre7E2gRVh61cS5vARn4QKBgQCNxp6jeal8LvHxI/R5Tjiur0Kc2y806BR79/ds
+HV70E8kszvpRJGp1IdXblq7hT79FmAjaPdcHxtEV201vqN7eORJ0m1/mZ1h8gBKr
+oJkGzMPj5/+V6zwMWPdEFtw9EqgeOwatMmRFOmkOx7DDEH4Ra3CF2cOoG7+BhMZq
+E3dk/QKBgQCYXqptB56sUrjnCXKEAdR96SDlVCmL7BBI893xDSAYIKhbpQsI2YY1
+dcFb02bnMbpqjkwHqpjHD8MJOWvXf8q/5FxDjHBSLSL8fM2PL9DI65c8MmwpHUSZ
+ZdcRhMrlN1iTkzw7WdfFCqb0HNl73sP5baqbRZgC+gysmDtgTZxBTQ==
+-----END RSA PRIVATE KEY-----