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/scripts/data_files/error.fmt b/scripts/data_files/error.fmt
index 3be94bd..6c2b487 100644
--- a/scripts/data_files/error.fmt
+++ b/scripts/data_files/error.fmt
@@ -56,7 +56,7 @@
             break;
     }
 
-    return( NULL );
+    return NULL ;
 }
 
 const char * mbedtls_low_level_strerr( int error_code )
@@ -79,7 +79,7 @@
             break;
     }
 
-    return( NULL );
+    return NULL ;
 }
 
 void mbedtls_strerror( int ret, char *buf, size_t buflen )