Fix RAM usage calculation

Author: facchinm

platform.txt

@@ -88,7 +88,7 @@ recipe.objcopy.hex.pattern="{compiler.path}{compiler.elf2hex.cmd}" {compiler.elf
 
 ## Compute size
 recipe.size.pattern="{compiler.path}{compiler.size.cmd}" -A "{build.path}/{build.project_name}.elf"
-recipe.size.regex.data=\.data\s+([0-9]+).*
+recipe.size.regex.data=^(?:\.data|\.bss)\s+([0-9]+).*
 recipe.size.regex=\.text\s+([0-9]+).*
 
 ## Save hex