i2c: pxa: clean up decode_bits()

Clean up decode_bits() to use pr_cont(), and move the newline into the
function rather than at its two callsites. Avoid printing an
unnecessary space before the newline.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Wolfram Sang <wsa@kernel.org>