Staging: comedi: Fix checpatch.pl issues in file rtd520.c

This patch fixes the checkpatch errors listed below:

ERROR: code indent should use tabs where possible
WARNING: space prohibited between function name and open parenthesis '('
WARNING: please, no spaces at the start of a line
WARNING: braces {} are not necessary for single statement blocks
WARNING: printk() should include KERN_ facility level

Signed-off-by: Nick Robinson <nr33@msstate.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>