soc/amd/picasso/include/acpi: introduce and use ACPI_SCI_IRQ definition

The newer AMD SoCs define ACPI_SCI_IRQ in the SoC's acpi.h header file
and use this definition in the mainboard code, so port this back to
Picasso.

Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: Ib569747aa388d7953e79de747905fb52c2a05e74
Reviewed-on: https://review.coreboot.org/c/coreboot/+/71912
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Fred Reitberger <reitbergerfred@gmail.com>

src/soc/amd/picasso/include/soc/acpi.h

@@ -8,6 +8,8 @@
 #include <device/device.h>
 #include <stdint.h>
 
+#define ACPI_SCI_IRQ 9
+
 /* RTC Registers */
 #define RTC_DATE_ALARM		0x0d