Don't set _FILE_OFFSET_BITS.

bionic doesn't support this for stdio on LP32 (and we don't think we ever
can, for ABI reasons), and LP64 you don't need to ask --- file offsets are
always 64-bit there.

This lets us move other parts of the tree (that don't use stdio) over to
64-bit offsets.

Bug: 11865851
Change-Id: I392c5757ae30da479f9ea0979afde1404f0af561