Fix parantheses on return and sizeof statements.

Used script:
```
import re
import sys

for arg in sys.argv[1:]:
    print(arg)
    with open(arg, 'r') as file:
        content = file.read()
        content = re.sub(r"return\s?\((?!.*\).*\()\s*\n?(.*)\n?\);", r"return \1;", \
            content, flags = re.M)
        content = re.sub(r"sizeof ([^\(][a-zA-Z0-9_\[\]]*)", r"sizeof(\1)",\
            content, flags = re.M)
    with open(arg, 'w') as file:
        file.write(content)

```
Executed with:
` find . -regextype posix-egrep -regex ".*\.([hc]|fmt|function)" | xargs -L1 python script.py`

Signed-off-by: Mateusz Starzyk <mateusz.starzyk@mobica.com>
diff --git a/include/mbedtls/error.h b/include/mbedtls/error.h
index 27420ce..b546d4d 100644
--- a/include/mbedtls/error.h
+++ b/include/mbedtls/error.h
@@ -163,7 +163,7 @@
     (void)file;
     (void)line;
 
-    return( high + low );
+    return high + low ;
 }
 
 /**