[MIPS] Allow united mipsel and mips64el gcc toolchain

Explicitly tell 32-bit links that they are doing 32-bit links.
This is needed when using united 32-bit and 64-bit toolchains.
This is harmless when using older separate 32-only toolchains.

(cherry picked from commit f541650828f75b3dab22c9c0caab845be78b80fc)

Change-Id: I8df0ee7d36c6409458e18bea4e0e8b132edf77dc
1 file changed