soc: mec: align SoC names defined in soc.yml to Kconfig SOC setting

This commit aligns the SoC names for mec SoCs defined in soc.yml to
Kconfig SOC setting.

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>

soc/microchip/mec/mec1501x/Kconfig.soc

@@ -17,4 +17,4 @@ config SOC_MEC1501_HSZ
 	select SOC_SERIES_MEC1501X
 
 config SOC
-	default "mec1501hsz" if SOC_MEC1501_HSZ
+	default "mec1501_hsz" if SOC_MEC1501_HSZ

soc/microchip/mec/mec172x/Kconfig.soc

@@ -21,5 +21,5 @@ config SOC_MEC172X_NLJ
 	select SOC_SERIES_MEC172X
 
 config SOC
-	default "mec172xnsz" if SOC_MEC172X_NSZ
-	default "mec172xnlj" if SOC_MEC172X_NLJ
+	default "mec172x_nsz" if SOC_MEC172X_NSZ
+	default "mec172x_nlj" if SOC_MEC172X_NLJ