Small valgrind suppression tweak for statically linked ffmpeg

tools/valgrind/memcheck/suppressions.txt

 # There are four kinds of suppressions in this file.
 # 1. third party stuff we have no control over
 #
 # 2. intentional unit test errors, or stuff that is somehow a false positive
 # in our own code, or stuff that is so trivial it's not worth fixing
 #
 # 3. Suppressions for real chromium bugs that are not yet fixed.
 # These should all be in chromium's bug tracking system (but a few aren't yet).
 # Periodically we should sweep this file and the bug tracker clean by
 # running overnight and removing outdated bugs/suppressions.
@@ skipping 3348 matching lines @@
    fun:pthread_setspecific
    ...
    fun:_ZN3gpu22InProcessCommandBuffer21InitializeOnGpuThreadERKNS0_27InitializeOnGpuThreadParamsE
 }
 {
    bug_441333
    Memcheck:Uninitialized
    fun:av_packet_unpack_dictionary
    fun:add_metadata_from_side_data
    fun:avcodec_decode_*
-   fun:avcodec_decode_*
 }
 {
    bug_448700_a
    Memcheck:Leak
    fun:_Znw*
    ...
    fun:_ZN10extensions11ApiTestBase15RegisterModulesEv
    fun:_ZN10extensions11ApiTestBase5SetUpEv
 }
 {
@@ skipping 159 matching lines @@
   buf_492821
   Memcheck:Uninitialized
   fun:_ZN5blink17CSSPropertyParser9validUnitEPNS_14CSSParserValueENS0_5UnitsENS_13CSSParserModeENS0_31ReleaseParsedCalcValueConditionE
   fun:_ZN5blink17CSSPropertyParser9validUnitEPNS_14CSSParserValueENS0_5UnitsENS0_31ReleaseParsedCalcValueConditionE
     fun:_ZN5blink17CSSPropertyParser18validWidthOrHeightEPNS_14CSSParserValueENS0_5UnitsE
     fun:_ZN5blink17CSSPropertyParser10parseValueENS_13CSSPropertyIDEb
     fun:_ZN5blink17CSSPropertyParser10parseValueENS_13CSSPropertyIDEbPNS_18CSSParserValueListERKNS_16CSSParserContextERN3WTF6VectorINS_11CSSPropertyELm256ENS7_16DefaultAllocatorEEENS_13StyleRuleBase4TypeE
     fun:_ZN5blink13CSSParserImpl23consumeDeclarationValueENS_19CSSParserTokenRangeENS_13CSSPropertyIDEbNS_13StyleRuleBase4TypeE
 fun:_ZN5blink13CSSParserImpl18consumeDeclarationENS_19CSSParserTokenRangeENS_13StyleRuleBase4TypeE
 }