ACPICA: Clarify/rename some root table descriptor fields

Original fields were not very descriptive and led to maintenance
problems.  New fields should help to understand the existing code.

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/acpica/tbfind.c

@@ -83,7 +83,7 @@ acpi_tb_find_table(char *signature,
 
 	/* Search for the table */
 
-	for (i = 0; i < acpi_gbl_root_table_list.count; ++i) {
+	for (i = 0; i < acpi_gbl_root_table_list.current_table_count; ++i) {
 		if (ACPI_MEMCMP(&(acpi_gbl_root_table_list.tables[i].signature),
 				header.signature, ACPI_NAME_SIZE)) {