avoid hiding stderr from dos2unix to make it easier to notice problems

[vith]

Now the output will end like this when silly people like me forget to install dos2unix like at #5 (comment):

$ make
...snip...
cc -c -DCRC="$(cat 1600x1200.crc)" -o 1600x1200.p 1600x1200.S
objcopy -Oihex 1600x1200.p 1600x1200.bin.ihex
dos2unix --quiet 1600x1200.bin.ihex
make: dos2unix: Command not found
make: *** [Makefile:33: 1600x1200.bin.ihex] Error 127
rm 1920x1080x120.00.bin.nocrc 1600x1200.bin.nocrc 1920x1080x120.00.crc 1600x1200.crc 1600x1200.p 1920x1080x120.00.o 1600x1200.o 1920x1080x120.00.p

[akatrevorjay]

Nice!

[akatrevorjay]

I'm not sure why I removed stderr output here to be honest, must have been an oversight on my end?