soc/amd/picasso: set is_rv to 1 for RV family

RV has difference in clk framework. In RV we get a 48Mhz fixed clk,
while in ST we had 25Mhz, 48mhz clocks and a Mux to select between them.
To differentiate set the fmw property to 1 for boards using RV family of SoC.

Signed-off-by: Akshu Agrawal <akshu.agrawal@amd.com>

BUG=b:158906189
TEST=rt5682 driver get the correct clk and tested audio playback

Change-Id: I685ded1607c2c7edc5e48f0bada258ebde192bb8
Reviewed-on: https://review.coreboot.org/c/coreboot/+/44009
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/soc/amd/picasso/acpi/sb_fch.asl

@@ -352,6 +352,14 @@ Device (MISC)
 	Name (_CRS, ResourceTemplate() {
 		Memory32Fixed (ReadWrite, ACPIMMIO_MISC_BASE, 0x100)
 	})
+	Name (_DSD, Package ()
+	{
+		ToUUID ("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+		Package ()
+		{
+			Package () { "is-rv", 1 },
+		},
+	})
 	Method (_STA, 0x0, NotSerialized)
 	{
 		Return (0x0F)