payloads/external/iPXE: Add more Kconfig options

Add two new options:
* Disable the prompt "Press Ctrl+B for the iPXE command line..."
Add a boolean that disables the initial 2 second timeout.

* Include a script that is executed instead of showing a shell.
Allows to add a script that will be included into the iPXE ROM.

Tested on Lenovo T500 and PC Engines apu2.

Change-Id: Ie1083d8571d9d1f1c7c71659fb6ff0de2eecad0e
Signed-off-by: Patrick Rudolph <siro@das-labor.org>
Signed-off-by: Michał Żygowski <michal.zygowski@3mdeb.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/20782
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

payloads/external/Makefile.inc

@@ -229,7 +229,9 @@ endif
 ifeq ($(CONFIG_BUILD_IPXE),y)
 PXE_ROM_FILE:=payloads/external/iPXE/ipxe/ipxe.rom
 endif
-
+ifeq ($(CONFIG_PXE_ADD_SCRIPT),y)
+PXE_CONFIG_SCRIPT:=$(abspath $(patsubst "%",%,$(CONFIG_PXE_SCRIPT)))
+endif
 ifeq ($(CONFIG_CONSOLE_SERIAL)$(CONFIG_DRIVERS_UART_8250IO),yy)
 IPXE_UART=COM$(call int-add,$(CONFIG_UART_FOR_CONSOLE) 1)
 endif
@@ -244,7 +246,7 @@ cbfs-files-$(CONFIG_PXE_ROM)$(CONFIG_BUILD_IPXE) += pci$(CONFIG_PXE_ROM_ID).rom
 pci$(CONFIG_PXE_ROM_ID).rom-file := $(PXE_ROM_FILE)
 pci$(CONFIG_PXE_ROM_ID).rom-type := raw
 
-payloads/external/iPXE/ipxe/ipxe.rom ipxe: $(DOTCONFIG)
+payloads/external/iPXE/ipxe/ipxe.rom ipxe: $(DOTCONFIG) $(PXE_CONFIG_SCRIPT)
 	$(MAKE) -C payloads/external/iPXE all \
 	CROSS_COMPILE="$(CROSS_COMPILE_$(ARCH-ramstage-y))" \
 	PXE_ROM_PCI_ID=$(PXE_ROM_PCI_ID) \
@@ -253,6 +255,9 @@ payloads/external/iPXE/ipxe/ipxe.rom ipxe: $(DOTCONFIG)
 	CONSOLE_SERIAL=$(IPXE_SERIAL_CONSOLE) \
 	IPXE_UART=$(IPXE_UART) \
 	CONFIG_TTYS0_BAUD=$(CONFIG_TTYS0_BAUD) \
+	CONFIG_SCRIPT=$(PXE_CONFIG_SCRIPT) \
+	CONFIG_HAS_SCRIPT=$(CONFIG_PXE_ADD_SCRIPT) \
+	CONFIG_PXE_NO_PROMT=$(CONFIG_PXE_NO_PROMT) \
 	MFLAGS= MAKEFLAGS=
 
 # LinuxBoot