For interrupt mode transfers, start with only TX interrupts enabled
to reduce the overall number of interrupts received. Once TX is
complete, enable RX interrupts to complete the transfer.
Reviewed-by: Viresh Kumar <viresh.kumar@st.com>
Signed-off-by: Chris Blair <chris.blair@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>