Move android_ids from .data.rel.ro to .rodata

Pages in .data.rel.ro are always dirty.  Move whatever we can to
.rodata so that we reduce memory pressure.

The size of rodata, text, and data.rel.ro sections of libc on cuttlefish
before/after this change:
    rodata: 0xfd70 -> 0x101d0 (+1120 bytes)
    text: 0xb5715 -> 0xb56e5 (-48 bytes)
    data.rel.ro: 0x57e0 -> 0x5230 (-1456 bytes)

While this change alone doesn't reduce the number of dirty pages
from data.rel.ro on cuttlefish, it is a step in that direction.

Test: Build and boot cuttlefish
Change-Id: Iff8203940495109dd01c40f31b034cfb2882e7f4