cmd/internal/obj/arm64: remove spurious assignments with OR
Use = rather than |= when assigning to an op variable.
Change-Id: I142c9fb3aa6f4b48875710100c05ab640e21933a
Reviewed-on: https://go-review.googlesource.com/c/go/+/461135 Reviewed-by: Eric Fang <eric.fang@arm.com> Reviewed-by: Than McIntosh <thanm@google.com>
Run-TryBot: Joel Sing <joel@sing.id.au>
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Cherry Mui <cherryyz@google.com>