Enable DSPr2 SIMD extensions if CPU type is mipsel

The DSPr2 extensions have been verified to work with little endian MIPS.
Whether or not CMAKE_SYSTEM_PROCESSOR is set to "mips" or "mipsel" in a
little endian MIPS environment seems to be inconsistent, but our build
system needs to handle both cases.
diff --git a/simd/CMakeLists.txt b/simd/CMakeLists.txt
index 346994c..8dbd7f1 100755
--- a/simd/CMakeLists.txt
+++ b/simd/CMakeLists.txt
@@ -262,7 +262,7 @@
 # MIPS (GAS)
 ###############################################################################
 
-elseif(CPU_TYPE STREQUAL "mips")
+elseif(CPU_TYPE STREQUAL "mips" OR CPU_TYPE STREQUAL "mipsel")
 
 enable_language(ASM)
 
@@ -293,7 +293,7 @@
   return()
 endif()
 
-add_library(simd OBJECT ${CPU_TYPE}/jsimd_dspr2.S ${CPU_TYPE}/jsimd.c)
+add_library(simd OBJECT mips/jsimd_dspr2.S mips/jsimd.c)
 
 if(CMAKE_POSITION_INDEPENDENT_CODE OR ENABLE_SHARED)
   set_target_properties(simd PROPERTIES POSITION_INDEPENDENT_CODE 1)