testfloat: fix dos2unix not found issue during do_unpack2

testfloat: fix dos2unix not found issue during do_unpack2

On some distros such as Ubuntu 10.04, dos2unix is replaced by
fromdos. Reference:
http://www.virtualhelp.me/linux/164-dos2unix-missing-ubuntu-1004

Fix the following error:
| NOTE: Applying patch 'TestFloat-powerpc-E500v2-SPE-1.patch'
| (../meta-fsl-ppc/recipes-test/testfloat/files/TestFloat-powerpc-E500v2
| -SPE-1.patch)
| ERROR: Error executing a python function in ../meta-fsl-ppc/recipes-test/testfloat/testfloat_2a.bb:
| CmdError: Command Error: exit status: 1  Output:

Signed-off-by: Ting Liu <b28495@freescale.com>