fate: Increase the tolerance in the lavr tests

A few fate instances on OS/2, OpenBSD, FreeBSD and IA64 linux currently
still fail a few tests with a maxdiff of 6.
Signed-off-by: Martin Storsjö <martin@martin.st>

tests/fate/libavresample.mak

@@ -30,7 +30,7 @@ fate-lavr-resample-$(3)-$(1)-$(2): tests/data/asynth-$(1)-1.wav
 fate-lavr-resample-$(3)-$(1)-$(2): CMD = avconv -i $(TARGET_PATH)/tests/data/asynth-$(1)-1.wav -ar $(2) -internal_sample_fmt $(3) -f $(4) -af atrim=end_sample=10240 -
 fate-lavr-resample-$(3)-$(1)-$(2): CMP = oneoff
 fate-lavr-resample-$(3)-$(1)-$(2): CMP_UNIT = $(5)
-fate-lavr-resample-$(3)-$(1)-$(2): FUZZ = 4
+fate-lavr-resample-$(3)-$(1)-$(2): FUZZ = 6
 fate-lavr-resample-$(3)-$(1)-$(2): REF = $(SAMPLES)/lavr/lavr-resample-$(3)-$(1)-$(2)
 endef