[dev.link] cmd/link: remove extSymPayload.gotype field
[dev.link] cmd/link: remove extSymPayload.gotype field

We have the information from auxs. Remove the field, slightly
reduce memory usage.

Change-Id: I3881777cfb40b03d0e2b0e7a326b0738080548b0
Reviewed-on: https://go-review.googlesource.com/c/go/+/233778
Run-TryBot: Cherry Zhang <d62e63aa42ce272d7b6a5055d97e942b33a34679@google.com>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Than McIntosh <4b2922593166fc595a9b1a408f34f5d3817fe9d2@google.com>

golang/go,cloudflare/go,CAFxX/go,golang/go,golang/go,CAFxX/go,nawawi/go,CAFxX/go,nawawi/go,cloudflare/go,cloudflare/go,nawawi/go,CAFxX/go,golang/go,golang/go,golang/go,cloudflare/go,nawawi/go,CAFxX/go,nawawi/go,CAFxX/go,cloudflare/go,CAFxX/go,cloudflare/go,cloudflare/go,nawawi/go,nawawi/go,CAFxX/go,golang/go,cloudflare/go,golang/go,nawawi/go