MetadataCrypt: extend timeout for low performance device

Some devices isolate CPUs under low battery. It causes
low performance and 5 sec timeout is soemtimes too short
for dm device ready.

Bug: 267989884

Change-Id: I52e1140b961ac42401a409e3264a5facc0f60cc4
Signed-off-by: Masaya Takahashi <masaya.a.takahashi@sony.com>