spi: cadence: Fix some checkpatch warnings

No functional change.
Fixing some style related issues

CHECK: multiple assignments should be avoided
+	new_ctrl_reg = ctrl_reg = cdns_spi_read(xspi, CDNS_SPI_CR);

CHECK: Alignment should match open parenthesis
+static void cdns_spi_config_clock_freq(struct spi_device *spi,
+				  struct spi_transfer *transfer)

CHECK: Please use a blank line after function/struct/union/enum declarations
+}
+static int cdns_prepare_message(struct spi_master *master,

Signed-off-by: Shubhrajyoti Datta <shubhraj@xilinx.com>
Signed-off-by: Mark Brown <broonie@kernel.org>