Staging: ti-st: smarten, reduce logs

Replace looping on the data buffers and printk-ing by
print_hex_dump.
Also replace most of the pr_info by pr_debug to reduce logging at
default loglevels (7 in our case..)

Signed-off-by: Pavan Savoy <pavan_savoy@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>