[MIPS]: Fix compiler error for mips32r2 dspr2

Fix error reported by llvm:
"error: unused variable 'kResampleAllpass1' [-Werror,-Wunused-const-variable]"
"error: unused variable 'kResampleAllpass2' [-Werror,-Wunused-const-variable]"

BUG=Unused variable.

Change-Id: I60c64b04e0fa96eb803416fb2148a81fc46a337d
Reviewed-on: https://chromium-review.googlesource.com/575132
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Commit-Queue: Karl Wiberg <kwiberg@webrtc.org>
Cr-Original-Commit-Position: refs/heads/master@{#19629}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 5b0690699dc84864544bd0b10028714533e7d02d
diff --git a/common_audio/signal_processing/resample_by_2_mips.c b/common_audio/signal_processing/resample_by_2_mips.c
index ec5fc8b..7885bea 100644
--- a/common_audio/signal_processing/resample_by_2_mips.c
+++ b/common_audio/signal_processing/resample_by_2_mips.c
@@ -19,9 +19,11 @@
 
 #include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"
 
+#if !defined(MIPS_DSP_R2_LE)
 // allpass filter coefficients.
 static const uint16_t kResampleAllpass1[3] = {3284, 24441, 49528};
 static const uint16_t kResampleAllpass2[3] = {12199, 37471, 60255};
+#endif
 
 // Multiply a 32-bit value with a 16-bit value and accumulate to another input:
 #define MUL_ACCUM_1(a, b, c) WEBRTC_SPL_SCALEDIFF32(a, b, c)