ARM: dts: aspeed: p10bmc: Define secure boot gpio

Input pin that indicates that the BMC is configured to boot with security
protections enforced.

Pulled up by default (secure). Placing the jumper will pull the pin down
(bypass security).

When in the secure boot state, it makes the EEPROM at 0x50 on bus 14
read only.

Link: https://lore.kernel.org/r/20210923074606.283393-1-joel@jms.id.auSigned-off-by: Joel Stanley <joel@jms.id.au>

arch/arm/boot/dts/aspeed-bmc-ibm-everest.dts

@@ -272,7 +272,7 @@ &gpio0 {
 				"factory-reset-toggle","",
 	/*G0-G7*/	"","","","","","","","",
 	/*H0-H7*/	"led-rtc-battery","led-bmc","led-rear-enc-id0","led-rear-enc-fault0","","","","",
-	/*I0-I7*/	"","","","","","","","",
+	/*I0-I7*/	"","","","","","","bmc-secure-boot","",
 	/*J0-J7*/	"","","","","","","","",
 	/*K0-K7*/	"","","","","","","","",
 	/*L0-L7*/	"","","","","","","","",

arch/arm/boot/dts/aspeed-bmc-ibm-rainier.dts

@@ -277,7 +277,7 @@ &gpio0 {
 	/*F0-F7*/	"","","","","","","","",
 	/*G0-G7*/	"","","","","","","","",
 	/*H0-H7*/	"","bmc-ingraham0","rear-enc-id0","rear-enc-fault0","","","","",
-	/*I0-I7*/	"","","","","","","","",
+	/*I0-I7*/	"","","","","","","bmc-secure-boot","",
 	/*J0-J7*/	"","","","","","","","",
 	/*K0-K7*/	"","","","","","","","",
 	/*L0-L7*/	"","","","","","","","",