board: phytec: common: Fix phytec_get_product_name()

Currently, phytec_get_product_name() function only takes care of PCM
SoM type, however in case of PCL, KSM or KSP SoM type it will return
error:

  phytec_get_product_name: Invalid SOM type

Add support for other SoM types as defined in phytec_som_type_str enum
(see phytec_som_detection.h) to get rid of the error.

While at it, also simplify switch case statements by grouping them
together. This makes it more concise and readable.

Signed-off-by: Primoz Fiser <primoz.fiser@norik.com>
Reviewed-by: Daniel Schultz <d.schultz@phytec.de>
diff --git a/board/phytec/common/phytec_som_detection.c b/board/phytec/common/phytec_som_detection.c
index 1f22139..4d7c9b9 100644
--- a/board/phytec/common/phytec_som_detection.c
+++ b/board/phytec/common/phytec_som_detection.c
@@ -295,17 +295,16 @@
 
 	switch (api2->som_type) {
 	case 0:
+	case 1:
+	case 2:
+	case 3:
 		som_type = api2->som_type;
 		break;
 	case 4:
-		som_type = 0;
-		break;
 	case 5:
 		som_type = 0;
 		break;
 	case 6:
-		som_type = 1;
-		break;
 	case 7:
 		som_type = 1;
 		break;