mb/asus/p8z77-series: Always select `INTEL_INT15`

The mainboard.c guard was only added to preserve reproducibility when
unifying the boards. The `install_intel_vga_int15_handler` function does
nothing when `VGA_ROM_RUN` is not selected. Remove the guard and always
select `INTEL_INT15` for simplicity.

Change-Id: If38ca49dba81921a3e7abe22542ae74d8914a38d
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/54412
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

src/mainboard/asus/p8z77-series/Kconfig

@@ -7,6 +7,7 @@ config BOARD_ASUS_P8Z77_SERIES
 	select HAVE_CMOS_DEFAULT
 	select HAVE_OPTION_TABLE
 	select INTEL_GMA_HAVE_VBT
+	select INTEL_INT15
 	select MAINBOARD_HAS_LIBGFXINIT
 	select NORTHBRIDGE_INTEL_SANDYBRIDGE
 	select SERIRQ_CONTINUOUS_MODE

src/mainboard/asus/p8z77-series/Kconfig.name

@@ -3,7 +3,6 @@ config BOARD_ASUS_P8Z77_M_PRO
 	select BOARD_ASUS_P8Z77_SERIES
 	select BOARD_ROMSIZE_KB_8192
 	select DRIVERS_ASMEDIA_ASPM_BLACKLIST # for ASM1061 eSATA
-	select INTEL_INT15
 	select MAINBOARD_HAS_LPC_TPM
 	select MAINBOARD_HAS_TPM1
 	select SUPERIO_NUVOTON_NCT6779D

src/mainboard/asus/p8z77-series/mainboard.c

@@ -1,8 +1,5 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
-/* TODO: remove */
-#if CONFIG(INTEL_INT15)
-
 #include <device/device.h>
 #include <drivers/intel/gma/int15.h>
 
@@ -17,5 +14,3 @@ static void mainboard_enable(struct device *dev)
 struct chip_operations mainboard_ops = {
 	.enable_dev = mainboard_enable
 };
-
-#endif