Using and operation when detecting Loongson mmi instructions
Using and operation when detecting Loongson mmi instructions

The Loongson 64-bit simd optimizations has used LEXT1(LoongISA general EXTensions 1),
so we must make sure loongson-mmi and loongson-ext exist at the same time.

GuangweiWang/openh264,mstorsjo/openh264,mstorsjo/openh264,cisco/openh264,GuangweiWang/openh264,mstorsjo/openh264,GuangweiWang/openh264,GuangweiWang/openh264,mstorsjo/openh264,GuangweiWang/openh264,mstorsjo/openh264,cisco/openh264,mstorsjo/openh264,cisco/openh264,cisco/openh264,mstorsjo/openh264,cisco/openh264,GuangweiWang/openh264,cisco/openh264,GuangweiWang/openh264,cisco/openh264