rockchip: spi: consistently use false/true with rkspi_enable_chip

While rkspi_enable_chip is called with true/false everywhere else in
the file, one call site uses '0' to denot 'false'.
This change this one parameter to 'false' and effects consistency.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
diff --git a/drivers/spi/rk_spi.c b/drivers/spi/rk_spi.c
index e7b2df8..aaf244d 100644
--- a/drivers/spi/rk_spi.c
+++ b/drivers/spi/rk_spi.c
@@ -277,7 +277,7 @@
 	uint ctrlr0;
 
 	/* Disable the SPI hardware */
-	rkspi_enable_chip(regs, 0);
+	rkspi_enable_chip(regs, false);
 
 	if (priv->speed_hz != priv->last_speed_hz)
 		rkspi_set_clk(priv, priv->speed_hz);