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/programs/test/selftest.c b/programs/test/selftest.c
index c7bcc53..72180bb 100644
--- a/programs/test/selftest.c
+++ b/programs/test/selftest.c
@@ -147,7 +147,7 @@
     mbedtls_free( empty2 );
     mbedtls_free( buffer1 );
     mbedtls_free( buffer2 );
-    return( failures );
+    return failures ;
 }
 #endif /* MBEDTLS_SELF_TEST */
 
@@ -165,10 +165,10 @@
         ref_ret != ret ||
         memcmp( buf + n, ref + n, sizeof( buf ) - n ) != 0 )
     {
-        return( 1 );
+        return 1 ;
     }
 
-    return( 0 );
+    return 0 ;
 }
 
 static int run_test_snprintf( void )
@@ -220,7 +220,7 @@
 #if defined(MBEDTLS_ENTROPY_NV_SEED) && !defined(MBEDTLS_NO_PLATFORM_ENTROPY)
     create_entropy_seed_file( );
 #endif
-    return( mbedtls_entropy_self_test( verbose ) );
+    return mbedtls_entropy_self_test( verbose ) ;
 }
 #endif
 
@@ -235,7 +235,7 @@
 #endif
     }
     mbedtls_memory_buffer_alloc_free( );
-    return( mbedtls_memory_buffer_alloc_self_test( verbose ) );
+    return mbedtls_memory_buffer_alloc_self_test( verbose ) ;
 }
 #endif