Remove file base name collisions.

CMakeLists.txt

av1/av1_common.mk

av1/av1_cx.mk

av1/common/av1_loopfilter.c

av1/common/av1_loopfilter.h

av1/common/mips/dspr2/av1_itrans16_dspr2.c

av1/common/mips/dspr2/av1_itrans4_dspr2.c

av1/common/mips/dspr2/av1_itrans8_dspr2.c

av1/common/mips/msa/av1_idct16x16_msa.c

av1/common/mips/msa/av1_idct4x4_msa.c

av1/common/mips/msa/av1_idct8x8_msa.c

av1/common/onyxc_int.h

av1/common/seg_common.c

av1/common/thread_common.c

av1/common/thread_common.h

av1/decoder/decoder.c

av1/encoder/arm/neon/quantize_neon.c

av1/encoder/av1_quantize.c

av1/encoder/av1_quantize.h

av1/encoder/encodemb.c