mb/hp/z220: Fix VGA graphics init

The VGA port has the DDC on port B.
Select the correct Kconfig and fix graphics init failing on VGA.

Tested on HP Z220, libgfxinit reports success and SeaBIOS is displayed
on the connected VGA monitor.

Change-Id: Ie5ec1a2d4606a21e1dc4217ff6fefe5ee35ac543
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/39629
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>

src/mainboard/hp/z220_sff_workstation/Kconfig

@@ -17,6 +17,7 @@ config BOARD_SPECIFIC_OPTIONS
 	select SUPERIO_NUVOTON_NPCD378
 	select MAINBOARD_HAS_LIBGFXINIT
 	select INTEL_GMA_HAVE_VBT
+	select GFX_GMA_ANALOG_I2C_HDMI_B
 
 config VBOOT
 	select VBOOT_VBNV_CMOS