payloads/tianocore: Add prompt for Boot Timeout

Add prompt to Boot Timeout so that it can be easily configured
from a config file.

Signed-off-by: Sean Rhodes <sean@starlabs.systems>
Change-Id: I62b8f0a9b5bc0796506b991199a457d6b34ae494
Reviewed-on: https://review.coreboot.org/c/coreboot/+/62558
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Matt DeVillier <matt.devillier@gmail.com>
diff --git a/payloads/external/tianocore/Kconfig b/payloads/external/tianocore/Kconfig
index 4194290..2cfe9ce 100644
--- a/payloads/external/tianocore/Kconfig
+++ b/payloads/external/tianocore/Kconfig
@@ -127,7 +127,7 @@
 	  the default key of F2.
 
 config TIANOCORE_BOOT_TIMEOUT
-	int
+	int "Set the timeout for boot menu prompt"
 	default 2
 	help
 	  The length of time in seconds for which the boot splash/menu prompt will be displayed.