'pr_debug' [-Werror=implicit-function-declaration]

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Acked-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
=Ð