mb/google/jecht: Set SMBIOS system type

Jecht variants will now correctly show their SMBIOS type as mini-pc
rather than the default desktop type.

Change-Id: I4f1be147bcfdad6247101db5b5943301466e60ad
Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/86459
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Singer <service+coreboot-gerrit@felixsinger.de>

src/mainboard/google/jecht/Kconfig

@@ -13,6 +13,7 @@ config BOARD_GOOGLE_BASEBOARD_JECHT
 	select MAINBOARD_HAS_TPM1
 	select SOC_INTEL_BROADWELL
 	select SUPERIO_ITE_IT8772F
+	select SYSTEM_TYPE_MINIPC
 
 config BOARD_GOOGLE_GUADO
 	select BOARD_GOOGLE_BASEBOARD_JECHT