uname_linux: Build for 32bit MIPS too

Since Go 1.8 32bit MIPS Big/Little Endian are supported assuming the
target runs Linux and the kernel either emulates an FPU or can access
the CPU one.

This allows the node_collector to build for mips and mipsle opening up
the possibility of running it on things like home routers
(DD-|Open|ASUS-)Wrt firmware usually has the necessary bits in place.

collector/uname_linux_int8.go

@@ -11,7 +11,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// +build !nouname,linux,386 !nouname,linux,amd64 !nouname,linux,arm64 !nouname,linux,mips64 !nouname,linux,mips64le
+// +build 386 amd64 arm64 mips64 mips64le mips mipsle
+// +build linux
+// +build !nouname
 
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