tests: spi_loopback: Fix frdm_ke17z overlay

The ke17z overlay for this test is incorrect in that the chip select
line sent to the spi pins on the header is PCS1, not PCS0. This is
having no functional effect on the test right now but soon I am trying
to implement a chip select test, and regardless it helps to have the CS
actually toggle right now for debugging purposes.

Also, I checked the frdm_ke17z512 and it looks like the board pinctrl
file is configuring for PCS2, so I fixed that as well because it looks
also like the same mistake, but I don't have that hardware.

Signed-off-by: Declan Snyder <[email protected]>

Author: decsny

tests/drivers/spi/spi_loopback/boards/frdm_ke17z.overlay

@@ -9,14 +9,14 @@
  */
 
 &lpspi0 {
-	slow@0 {
+	slow@1 {
 		compatible = "test-spi-loopback-slow";
-		reg = <0>;
+		reg = <1>;
 		spi-max-frequency = <500000>;
 	};
-	fast@0 {
+	fast@1 {
 		compatible = "test-spi-loopback-fast";
-		reg = <0>;
+		reg = <1>;
 		spi-max-frequency = <16000000>;
 	};
 };

tests/drivers/spi/spi_loopback/boards/frdm_ke17z512.overlay

@@ -9,14 +9,14 @@
  */
 
 &lpspi0 {
-	slow@0 {
+	slow@2 {
 		compatible = "test-spi-loopback-slow";
-		reg = <0>;
+		reg = <2>;
 		spi-max-frequency = <500000>;
 	};
-	fast@0 {
+	fast@2 {
 		compatible = "test-spi-loopback-fast";
-		reg = <0>;
+		reg = <2>;
 		spi-max-frequency = <16000000>;
 	};
 };