UPSTREAM: crypto: mips: add poly1305-core.S to .gitignore

poly1305-core.S is an auto-generated file, so it should be ignored.

Fixes: a11d055e ("crypto: mips/poly1305 - incorporate OpenSSL/CRYPTOGAMS optimized implementation")
Signed-off-by: Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
(cherry picked from commit dc92d0df)
Bug: 187129171
Signed-off-by: Connor O'Brien <connoro@google.com>
Change-Id: I85443ad8b0e5d6b2613c2a075f96c6d819f3e1b5