spi: mchp-pci1xxxx: Fix length of SPI transactions not set properly in driver

In pci1xxxx_spi_transfer_one API, length of SPI transaction gets cleared
by setting of length mask. Set length of transaction only after masking
length field.

Fixes: 1cc0cbe ("spi: microchip: pci1xxxx: Add driver for SPI controller of PCI1XXXX PCIe switch")
Signed-off-by: Tharun Kumar P <tharunkumar.pasumarthi@microchip.com>
Link: https://lore.kernel.org/r/20230404171613.1336093-2-tharunkumar.pasumarthi@microchip.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: Tharun Kumar P

drivers/spi/spi-pci1xxxx.c

@@ -199,8 +199,9 @@ static int pci1xxxx_spi_transfer_one(struct spi_controller *spi_ctlr,
 			else
 				regval &= ~SPI_MST_CTL_MODE_SEL;
 
-			regval |= ((clkdiv << 5) | SPI_FORCE_CE | (len << 8));
+			regval |= ((clkdiv << 5) | SPI_FORCE_CE);
 			regval &= ~SPI_MST_CTL_CMD_LEN_MASK;
+			regval |= (len << 8);
 			writel(regval, par->reg_base +
 			       SPI_MST_CTL_REG_OFFSET(p->hw_inst));
 			regval = readl(par->reg_base +