examples, components: remove C/C++ standard overrides

...where they are not necessary after switching to C17 and C++20.

components/driver/CMakeLists.txt

@@ -127,6 +127,3 @@ else()
                         REQUIRES esp_pm esp_ringbuf freertos soc hal esp_hw_support
                         LDFRAGMENTS linker.lf)
 endif()
-
-# uses C11 atomic feature
-set_source_files_properties(spi_master.c PROPERTIES COMPILE_FLAGS -std=gnu11)

components/esp_eth/CMakeLists.txt

@@ -53,6 +53,3 @@ idf_component_register(SRCS "${srcs}"
                        INCLUDE_DIRS ${include}
                        REQUIRES "esp_event" # For using "ESP_EVENT_DECLARE_BASE" in header file
                        PRIV_REQUIRES ${priv_requires})
-
-# uses C11 atomic feature
-set_source_files_properties(src/esp_eth.c PROPERTIES COMPILE_FLAGS -std=gnu11)

components/esp_event/CMakeLists.txt

@@ -25,8 +25,3 @@ idf_component_register(SRCS ${srcs}
                     REQUIRES ${requires}
                     PRIV_REQUIRES ${priv_requires}
                     LDFRAGMENTS linker.lf)
-
-if(CONFIG_ESP_EVENT_LOOP_PROFILING)
-    # uses C11 atomic feature
-    set_source_files_properties(esp_event.c PROPERTIES COMPILE_FLAGS -std=gnu11)
-endif()