MIPS: MSP71xx: Move code.

Now that Yosemite's gone we can move the MSP71xx code one level up.

Shane McDonald <mcdonald.shane@gmail.com>'s
https://patchwork.linux-mips.org/patch/4736/ has been folded into this
patch.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/Kbuild.platforms b/arch/mips/Kbuild.platforms
index c7ea3a0..5c08849 100644
--- a/arch/mips/Kbuild.platforms
+++ b/arch/mips/Kbuild.platforms
@@ -18,7 +18,7 @@
 platforms += mti-malta
 platforms += mti-sead3
 platforms += netlogic
-platforms += pmc-sierra
+platforms += pmcs-msp71xx
 platforms += pnx833x
 platforms += powertv
 platforms += rb532