staging: gasket: page_table: use total_entries for max ext lvl0 page idx

The maximum number of entries in the page table is configurable at
initialization time and should be used in gasket_extended_lvl0_page_idx.
Signed-off-by: Nick Ewalt <nicholasewalt@google.com>
Signed-off-by: Todd Poynor <toddpoynor@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/gasket/gasket_page_table.c

@@ -562,7 +562,7 @@ static ulong gasket_extended_lvl0_page_idx(struct gasket_page_table *pg_tbl,
 					   ulong dev_addr)
 {
 	return (dev_addr >> GASKET_EXTENDED_LVL0_SHIFT) &
-	       ((1 << GASKET_EXTENDED_LVL0_WIDTH) - 1);
+		(pg_tbl->config.total_entries - 1);
 }
 
 /*