ARM: OMAP2+: mux: Replace three seq_printf() calls by seq_puts()

Strings which did not contain data format specification should be put into
a sequence. Thus use the corresponding function "seq_puts".

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Tony Lindgren <tony@atomide.com>