minor fix

Author: Sarthak-Shaha

third_party/silabs/efr32_sdk.gni

@@ -99,7 +99,7 @@ silabs_common_plat_dir = "${chip_root}/examples/platform/silabs"
 silabs_platform_dir = "${chip_root}/src/platform/silabs"
 
 is_series_2 = silabs_family == "mgm24" || silabs_family == "efr32mg24" ||
-              silabs_family == "efr32mg26"
+              silabs_family == "efr32mg26" || silabs_family == "mgm26"
 
 assert(efr32_sdk_root != "", "efr32_sdk_root must be specified")