ffmpeg: replace tabulators with spaces for consistency

ffmpeg: replace tabulators with spaces for consistency

`omapfbplay*.bb` recipes use tabulators consistently and therefore they are not changed.

Use

	grep -e $'\t' ffmpeg_*bb

to find tabulators in Bash [1].

[1] http://www.claudiokuenzler.com/blog/99/tabulator-in-bash

Signed-off-by: Paul Menzel <paulepanter@users.sourceforge.net>
Signed-off-by: Khem Raj <raj.khem@gmail.com>