Commit 930beb5a ("MIPS: introduce MIPS_L1_CACHE_SHIFT_<N>") forgot
to select the correct MIPS_L1_CACHE_SHIFT for SNI RM. This breaks non
coherent DMA because of a wrong allocation alignment.

Fixes: 930beb5a ("MIPS: introduce MIPS_L1_CACHE_SHIFT_<N>")
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>