Fix error in clocks leading to devices staying unlocked

Use BOOTTIME consistently!

Bug: 18246810
Change-Id: I630bf39f72ab69f971d2f772e8d4545ffe467b82
diff --git a/cryptfs.c b/cryptfs.c
index e9d6afb..2a6586b 100644
--- a/cryptfs.c
+++ b/cryptfs.c
@@ -3739,7 +3739,7 @@
 char* cryptfs_get_password()
 {
     struct timespec now;
-    clock_gettime(CLOCK_MONOTONIC, &now);
+    clock_gettime(CLOCK_BOOTTIME, &now);
     if (now.tv_sec < password_expiry_time) {
         return password;
     } else {