target-mips: Add ASE DSP internal functions

Add internal functions using by MIPS ASE DSP instructions.
Signed-off-by: NJia Liu <proljc@gmail.com>
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>

target-mips/Makefile.objs

-obj-y += translate.o op_helper.o lmi_helper.o helper.o cpu.o
+obj-y += translate.o dsp_helper.o op_helper.o lmi_helper.o helper.o cpu.o
 obj-$(CONFIG_SOFTMMU) += machine.o