add cmake support for g0, exlicitly call HAL_Init() and also HAL_IncTick() in systick irq, fix button active state.

tools/cmake/cpu/cortex-m0plus.cmake

@@ -0,0 +1,11 @@
+if (TOOLCHAIN STREQUAL "gcc")
+  list(APPEND TOOLCHAIN_COMMON_FLAGS
+    -mthumb
+    -mcpu=cortex-m0plus
+    -mfloat-abi=soft
+    )
+
+  set(FREERTOS_PORT GCC_ARM_CM0 CACHE INTERNAL "")
+else ()
+  # TODO support IAR
+endif ()