Add Intel Jasper Lake support

Loosely based on commit b01d7e9f (ichspi: Add Jasper Lake support)
on flashrom master.

Besides a little change in descriptor detection, no difference to
Cannon Point was found. Hence, add new PCI IDs as 300 series.

Change-Id: I9c715c1a5f1ceea32dc51669453d89b315ba8ca2
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/flashrom-stable/+/71453
Reviewed-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-by: Paul Menzel <paulepanter@mailbox.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/ich_descriptors.c b/ich_descriptors.c
index fb050c2..bad2b33 100644
--- a/ich_descriptors.c
+++ b/ich_descriptors.c
@@ -1028,8 +1028,12 @@
 			return CHIPSET_500_SERIES_TIGER_POINT;
 		if (content->CSSL == 0x14) /* backwards compatible Alder Point */
 			return CHIPSET_500_SERIES_TIGER_POINT;
-		if (content->CSSL == 0x03)
-			return CHIPSET_ELKHART_LAKE;
+		if (content->CSSL == 0x03) {
+			if (content->CSSO == 0x58)
+				return CHIPSET_ELKHART_LAKE;
+			else if (content->CSSO == 0x6c) /* backwards compatible Jasper Lake */
+				return CHIPSET_300_SERIES_CANNON_POINT;
+		}
 		msg_pwarn("Unknown flash descriptor, assuming 500 series compatibility.\n");
 		return CHIPSET_500_SERIES_TIGER_POINT;
 	}