fate: update pcx reference

It changed because encoder now writes 0/1 for
sample aspect ratio instead of 0/0.
Signed-off-by: Paul B Mahol <onemda@gmail.com>

tests/ref/lavf/pcx

-2df1d747fba23d03b6ff9c91b8b465c9 *./tests/data/images/pcx/02.pcx
+c4faf65ecc812ec8412cc26140c13bd5 *./tests/data/images/pcx/02.pcx
 ./tests/data/images/pcx/%02d.pcx CRC=0x6da01946
 364147 ./tests/data/images/pcx/02.pcx