hw/display/sm501: Replace i2c_send_recv() by i2c_recv() & i2c_send()

Instead of using the confuse i2c_send_recv(), rewrite to directly
call i2c_recv() & i2c_send(), resulting in code easier to review.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Corey Minyard <cminyard@mvista.com>

hw/display/sm501.c

@@ -1033,17 +1033,18 @@ static void sm501_i2c_write(void *opaque, hwaddr addr, uint64_t value,
     case SM501_I2C_CONTROL:
         if (value & SM501_I2C_CONTROL_ENABLE) {
             if (value & SM501_I2C_CONTROL_START) {
+                bool is_recv = s->i2c_addr & 1;
                 int res = i2c_start_transfer(s->i2c_bus,
                                              s->i2c_addr >> 1,
-                                             s->i2c_addr & 1);
+                                             is_recv);
                 if (res) {
                     s->i2c_status |= SM501_I2C_STATUS_ERROR;
                 } else {
                     int i;
                     for (i = 0; i <= s->i2c_byte_count; i++) {
-                        res = i2c_send_recv(s->i2c_bus, &s->i2c_data[i],
-                                            !(s->i2c_addr & 1));
-                        if (res) {
+                        if (is_recv) {
+                            s->i2c_data[i] = i2c_recv(s->i2c_bus);
+                        } else if (i2c_send(s->i2c_bus, s->i2c_data[i]) < 0) {
                             s->i2c_status |= SM501_I2C_STATUS_ERROR;
                             return;
                         }