mb/hp/compaq_elite_8300_usdt: enable mSATA

Tested with a Kingston UV500.
It works the same (3Gb/s) as with vendor FW.

According to smartctl -a /dev/sda:
SATA Version is:  SATA 3.1, 6.0 Gb/s (current: 3.0 Gb/s)

Change-Id: I5c714351586e6084029ce4c54fb47cbae4d3405b
Signed-off-by: Riku Viitanen <riku.viitanen@protonmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/77376
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-by: Paul Menzel <paulepanter@mailbox.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Singer <service+coreboot-gerrit@felixsinger.de>
diff --git a/src/mainboard/hp/compaq_elite_8300_usdt/devicetree.cb b/src/mainboard/hp/compaq_elite_8300_usdt/devicetree.cb
index ba4ac6d..f7f321f 100644
--- a/src/mainboard/hp/compaq_elite_8300_usdt/devicetree.cb
+++ b/src/mainboard/hp/compaq_elite_8300_usdt/devicetree.cb
@@ -9,9 +9,9 @@
 			register "pcie_hotplug_map" = "{ 0, 0, 0, 0, 0, 0, 0, 0 }"
 			register "pcie_port_coalesce" = "1"
 			register "sata_interface_speed_support" = "0x3"
-			register "sata_port_map" = "0x3"  # 0x1: 2.5" slot
+			register "sata_port_map" = "0x7"  # 0x1: 2.5" slot
 			                                  # 0x2: DVD
-			                                  # 0x?: mSATA
+			                                  # 0x4: mSATA
 			register "spi_lvscc" = "0x2005"
 			register "spi_uvscc" = "0x2005"
 			register "superspeed_capable_ports" = "0x0000000f"