This patch fixes regresion introduced in CL:
https://chromium-review.googlesource.com/c/489525/

ldr instruction is unaligned load on MIPS and it is not available in
MIPS64r6 architecture.

BUG=

Review-Url: https://codereview.chromium.org/2873873005
Cr-Commit-Position: refs/heads/master@{#45257}