mb/google/poppy/variants/nami: Load pantheon VBT binary

Load pantheon.bin by reading sku-id.

BUG=b:78663963
TEST=Boots to OS and display comes up.
     Check the board specific vbt binary loaded.

Change-Id: I66cb43d87363b3e8b1a1498cdae8eeeb8b75219d
Signed-off-by: Ivy Jian <ivy_jian@compal.corp-partner.google.com>
Reviewed-on: https://review.coreboot.org/26267
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/poppy/variants/nami/include/variant/sku.h

@@ -20,5 +20,7 @@
 #define SKU_0_NAMI	0x3A7B
 #define SKU_1_VAYNE	0x3A63
 #define SKU_2_VAYNE	0x3A7F
+#define SKU_0_PANTHEON	0x3F63
+#define SKU_1_PANTHEON	0x3F67
 
 #endif /* __MAINBOARD_SKU_H__ */

src/mainboard/google/poppy/variants/nami/mainboard.c

@@ -146,6 +146,9 @@ const char *mainboard_vbt_filename(void)
 	uint32_t sku_id = variant_board_sku();
 
 	switch (sku_id) {
+	case SKU_0_PANTHEON:
+	case SKU_1_PANTHEON:
+		return "vbt-pantheon.bin";
 	default:
 		return "vbt.bin";
 		break;