ACPICA: Ignore ACPI table signature for Load() operator

Only "SSDT" is acceptable to the ACPI spec, but tables are
seen with OEMx and null sigs. Therefore, signature validation
is worthless.  Apparently MS ACPI accepts such signatures, ACPICA
must be compatible.

http://bugzilla.kernel.org/show_bug.cgi?id=10454

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/tables/tbinstal.c

@@ -123,24 +123,13 @@ acpi_tb_add_table(struct acpi_table_desc *table_desc,
 		}
 	}
 
-	/* The table must be either an SSDT or a PSDT or an OEMx */
-
-	if (!ACPI_COMPARE_NAME(table_desc->pointer->signature, ACPI_SIG_PSDT)&&
-	    !ACPI_COMPARE_NAME(table_desc->pointer->signature, ACPI_SIG_SSDT)&&
-	    strncmp(table_desc->pointer->signature, "OEM", 3)) {
-		/* Check for a printable name */
-		if (acpi_ut_valid_acpi_name(
-			*(u32 *) table_desc->pointer->signature)) {
-			ACPI_ERROR((AE_INFO, "Table has invalid signature "
-					"[%4.4s], must be SSDT or PSDT",
-				    table_desc->pointer->signature));
-		} else {
-			ACPI_ERROR((AE_INFO, "Table has invalid signature "
-					"(0x%8.8X), must be SSDT or PSDT",
-				    *(u32 *) table_desc->pointer->signature));
-		}
-		return_ACPI_STATUS(AE_BAD_SIGNATURE);
-	}
+	/*
+	 * Originally, we checked the table signature for "SSDT" or "PSDT" here.
+	 * Next, we added support for OEMx tables, signature "OEM".
+	 * Valid tables were encountered with a null signature, so we've just
+	 * given up on validating the signature, since it seems to be a waste
+	 * of code. The original code was removed (05/2008).
+	 */
 
 	(void)acpi_ut_acquire_mutex(ACPI_MTX_TABLES);