Fix for psplash segmentation fault

Fix for psplash segmentation fault

Fix segmentation fault when passing -a without angel value.

When psplash -a is called instead of psplash -a<angle value>
it will segmentation fault calling out of bound argv[].

git://git.yoctoproject.org/psplash

Signed-of-by: Aws Ismail<aws.ismail@windriver.com>
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