crypto/internal/fips: avoid some non-relocatable global initializers

crypto/internal/fips: avoid some non-relocatable global initializers

In normal code,

	var x = []int{...}

will be laid out by the linker, but in FIPS packages, the slice
assignment has to be deferred to init time to avoid a global
data relocation. We can avoid the init time work by writing

	var x = [...]int{...}

instead. Do that.

For #69536.

Change-Id: Ie3c1d25af3f79182ee254014e49d3711038aa327
Reviewed-on: https://go-review.googlesource.com/c/go/+/625815
Reviewed-by: Filippo Valsorda <filippo@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>