ACPI/table: Always count matched and successfully parsed entries

acpi_parse_entries() allows to traverse all available table entries (aka
subtables) by passing max_entries parameter equal to 0, but since its count
variable is only incremented if max_entries is not 0, the function always
returns 0 for max_entries equal to 0.  It would be more useful if it returned
the number of entries matched instead, so make it increment count in that
case too.

Signed-off-by: Tomasz Nowicki <tomasz.nowicki@linaro.org>
[Linux commit 4ceacd02f5a1795c5c697e0345ee10beef675290]
Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>

xen/drivers/acpi/tables.c

@@ -239,10 +239,13 @@ acpi_table_parse_entries(char *id,
 		}
 
 		if (entry->type == entry_id
-		    && (!max_entries || count++ < max_entries))
+		    && (!max_entries || count < max_entries)) {
 			if (handler(entry, table_end))
 				return -EINVAL;
 
+			count++;
+		}
+
 		entry = (struct acpi_subtable_header *)
 		    ((unsigned long)entry + entry->length);
 	}