mb/prodrive/atlas: Enable resizable BAR support

Allow up to 4GiB resizable BAR support.

Signed-off-by: Lean Sheng Tan <sheng.tan@9elements.com>
Change-Id: I097483ba8b4479211f67f29a42754d1a51379771
Reviewed-on: https://review.coreboot.org/c/coreboot/+/67379
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

src/mainboard/prodrive/atlas/Kconfig

@@ -3,14 +3,15 @@ config BOARD_PRODRIVE_ATLAS_BASEBOARD
 	select BOARD_ROMSIZE_KB_32768
 	select INTEL_LPSS_UART_FOR_CONSOLE
 	select EC_ACPI
+	select FSP_TYPE_IOT
 	select HAVE_ACPI_RESUME
 	select HAVE_ACPI_TABLES
 	select INTEL_GMA_HAVE_VBT
 	select MAINBOARD_HAS_TPM2
 	select MAINBOARD_USES_IFD_EC_REGION
 	select MEMORY_MAPPED_TPM
+	select PCIEXP_SUPPORT_RESIZABLE_BARS
 	select SOC_INTEL_ALDERLAKE_PCH_P
-	select FSP_TYPE_IOT
 
 if BOARD_PRODRIVE_ATLAS_BASEBOARD
 
@@ -42,4 +43,8 @@ config CBFS_SIZE
 config NO_POST
 	default y
 
+config PCIEXP_DEFAULT_MAX_RESIZABLE_BAR_BITS
+	int
+	default 32
+
 endif #BOARD_PRODRIVE_ATLAS_BASEBOARD