config/coreboot: Add Dell Latitude E4300

Add patches to convert the E6400 port into a GM45 Latitude variant and
add the E4300 as another variant, and create a config for the E4300.
Tested on my E6400 and E4300.

Signed-off-by: Nicholas Chin <nic.c3.14@gmail.com>

config/coreboot/e6400nvidia_4mb/config/normal

@@ -105,10 +105,9 @@ CONFIG_VENDOR_DELL=y
 # CONFIG_VENDOR_SYSTEM76 is not set
 # CONFIG_VENDOR_TI is not set
 # CONFIG_VENDOR_UP is not set
-CONFIG_BOARD_SPECIFIC_OPTIONS=y
 CONFIG_MAINBOARD_PART_NUMBER="Latitude E6400"
 CONFIG_MAINBOARD_VERSION="1.0"
-CONFIG_MAINBOARD_DIR="dell/e6400"
+CONFIG_MAINBOARD_DIR="dell/gm45_latitude"
 CONFIG_VGA_BIOS_ID="10de,06eb"
 CONFIG_DIMM_MAX=4
 CONFIG_DIMM_SPD_SIZE=256
@@ -122,7 +121,8 @@ CONFIG_POST_DEVICE=y
 CONFIG_POST_IO=y
 CONFIG_DEVICETREE="devicetree.cb"
 # CONFIG_VBOOT is not set
-CONFIG_OVERRIDE_DEVICETREE=""
+CONFIG_VARIANT_DIR="e6400"
+CONFIG_OVERRIDE_DEVICETREE="variants/$(CONFIG_VARIANT_DIR)/overridetree.cb"
 CONFIG_VGA_BIOS=y
 # CONFIG_PCIEXP_ASPM is not set
 # CONFIG_PCIEXP_L1_SUB_STATE is not set
@@ -135,8 +135,9 @@ CONFIG_CMOS_LAYOUT_FILE="src/mainboard/$(MAINBOARDDIR)/cmos.layout"
 CONFIG_MAX_SOCKET=1
 CONFIG_BOOT_DEVICE_SPI_FLASH_BUS=0
 # CONFIG_CONSOLE_POST is not set
-CONFIG_BOARD_DELL_E6400=y
 # CONFIG_BOARD_DELL_LATITUDE_E7240 is not set
+# CONFIG_BOARD_DELL_E4300 is not set
+CONFIG_BOARD_DELL_E6400=y
 # CONFIG_BOARD_DELL_OPTIPLEX_3050 is not set
 # CONFIG_BOARD_DELL_OPTIPLEX_9020_SFF is not set
 # CONFIG_BOARD_DELL_OPTIPLEX_9020_MT is not set
@@ -154,6 +155,7 @@ CONFIG_BOARD_DELL_E6400=y
 # CONFIG_BOARD_DELL_OPTIPLEX_9010 is not set
 # CONFIG_BOARD_DELL_PRECISION_T1650 is not set
 # CONFIG_BOARD_DELL_XPS_8300 is not set
+CONFIG_BOARD_DELL_GM45_LATITUDE_COMMON=y
 CONFIG_INTEL_GMA_DPLL_REF_FREQ=100000000
 CONFIG_ECAM_MMCONF_BASE_ADDRESS=0xf0000000
 CONFIG_ECAM_MMCONF_BUS_NUMBER=64