include/acpi/acpi.h: Add ACPI_NAME_BUFFER_SIZE

ACPI names can only be 4 characters long. Define a constant that defines
the size of the name + the NUL terminator.

BUG=b:154756391
TEST=none

Signed-off-by: Raul E Rangel <rrangel@chromium.org>
Change-Id: Iad230c029f324005620ddad66c433ada26be78cc
Reviewed-on: https://review.coreboot.org/c/coreboot/+/43329
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/include/acpi/acpi.h b/src/include/acpi/acpi.h
index cd99899..35a1dc3 100644
--- a/src/include/acpi/acpi.h
+++ b/src/include/acpi/acpi.h
@@ -52,6 +52,8 @@
 #define RSDP_SIG		"RSD PTR "  /* RSDT pointer signature */
 #define ASLC			"CORE"      /* Must be exactly 4 bytes long! */
 
+#define ACPI_NAME_BUFFER_SIZE	5 /* 4 chars + 1 NUL */
+
 /*
  * The assigned ACPI ID for the coreboot project is 'BOOT'
  * http://www.uefi.org/acpi_id_list