Add bitness info to <transport>.

Only valid for transport == passthrough or toggled.
Example:
<transport>hwbinder</transport>
<transport arch="64">passthrough</transport>
<transport arch="32+64">passthrough</transport>
<transport arch="32">passthrough</transport>

Allow transport tag to be missing (for native HALs like GLES).

Bug: 35966597
Test: libvintf_test
Change-Id: I80928a5d46f3097ed18f2894e46762127b29bd4c
12 files changed