mb/google/sarien: Set system type for the board variants

Select the appropriate system type for the different variants of
the Sarien board.

This will allow the Arcada variant to use the tablet mode feature
of the Intel Virtual Button driver.

Change-Id: I8a829aab012256ec196c8ec0fa298fd2bc77f2e1
Signed-off-by: Duncan Laurie <dlaurie@google.com>
Reviewed-on: https://review.coreboot.org/c/31207
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Furquan Shaikh <furquan@google.com>

src/mainboard/google/sarien/Kconfig

@@ -20,7 +20,8 @@ config BOARD_GOOGLE_BASEBOARD_SARIEN
 	select SOC_INTEL_COMMON_BLOCK_HDA_VERB
 	select SOC_INTEL_COMMON_BLOCK_SMM_ESPI_ACPI_DIS
 	select SPD_READ_BY_WORD
-	select SYSTEM_TYPE_LAPTOP
+	select SYSTEM_TYPE_LAPTOP if BOARD_GOOGLE_SARIEN
+	select SYSTEM_TYPE_CONVERTIBLE if BOARD_GOOGLE_ARCADA
 	select TPM2
 	select MAINBOARD_USES_IFD_EC_REGION
 	select MAINBOARD_USES_IFD_GBE_REGION if BOARD_GOOGLE_SARIEN