OMAP: mux: Replace printk with pr_xxx macros

Replace all the printk(KERN_XXX... with pr_xxx macros.

Signed-off-by: Benoit Cousson <b-cousson@ti.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>