spi: au1550: Simplify au1550_spi_setupxfer()

SPI core validates both bits_per_word and speed_hz transfer parameters and
defaults to spi->bits_per_word and spi->max_speed_hz in case these per
transfer parameters are not set. This can simplify a little the
au1550_spi_setupxfer() as there is need to check only for valid
"struct spi_transfer" pointer.

Signed-off-by: Jarkko Nikula <[e-mail]>
Signed-off-by: Mark Brown <[e-mail]>

drivers/spi/spi-au1550.c

···
 	unsigned bpw, hz;
 	u32 cfg, stat;
 
-	bpw = spi->bits_per_word;
-	hz = spi->max_speed_hz;
 	if (t) {
-		if (t->bits_per_word)
-			bpw = t->bits_per_word;
-		if (t->speed_hz)
-			hz = t->speed_hz;
+		bpw = t->bits_per_word;
+		hz = t->speed_hz;
+	} else {
+		bpw = spi->bits_per_word;
+		hz = spi->max_speed_hz;
 	}
 
 	if (!hz)