Add support for armv7-sony-vita-newlibeabihf in v0.17

[pheki]

Support was originally added for v0.16 in #1640

[briansmith]

Thanks! If you want it to actually run decently then you should also submit a PR that changes the cpu::arm submodule to add a case for "vita" in this block:

    // TODO(MSRV): 32-bit ARM doesn't support any static feature detection yet.
    pub(in super::super) const STATIC_DETECTED: u32 = 0;

STATIC_DETECTED should indicate NEON support if the target_os is "vita", IIUC.

This will make all the crypto run much faster.