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/pkey/key_app_writer.c b/programs/pkey/key_app_writer.c
index 8a09af5..a61cda1 100644
--- a/programs/pkey/key_app_writer.c
+++ b/programs/pkey/key_app_writer.c
@@ -128,7 +128,7 @@
     if( opt.output_format == OUTPUT_FORMAT_PEM )
     {
         if( ( ret = mbedtls_pk_write_pubkey_pem( key, output_buf, 16000 ) ) != 0 )
-            return( ret );
+            return ret ;
 
         len = strlen( (char *) output_buf );
     }
@@ -136,24 +136,24 @@
 #endif
     {
         if( ( ret = mbedtls_pk_write_pubkey_der( key, output_buf, 16000 ) ) < 0 )
-            return( ret );
+            return ret ;
 
         len = ret;
         c = output_buf + sizeof(output_buf) - len;
     }
 
     if( ( f = fopen( output_file, "w" ) ) == NULL )
-        return( -1 );
+        return -1 ;
 
     if( fwrite( c, 1, len, f ) != len )
     {
         fclose( f );
-        return( -1 );
+        return -1 ;
     }
 
     fclose( f );
 
-    return( 0 );
+    return 0 ;
 }
 
 static int write_private_key( mbedtls_pk_context *key, const char *output_file )
@@ -170,7 +170,7 @@
     if( opt.output_format == OUTPUT_FORMAT_PEM )
     {
         if( ( ret = mbedtls_pk_write_key_pem( key, output_buf, 16000 ) ) != 0 )
-            return( ret );
+            return ret ;
 
         len = strlen( (char *) output_buf );
     }
@@ -178,24 +178,24 @@
 #endif
     {
         if( ( ret = mbedtls_pk_write_key_der( key, output_buf, 16000 ) ) < 0 )
-            return( ret );
+            return ret ;
 
         len = ret;
         c = output_buf + sizeof(output_buf) - len;
     }
 
     if( ( f = fopen( output_file, "w" ) ) == NULL )
-        return( -1 );
+        return -1 ;
 
     if( fwrite( c, 1, len, f ) != len )
     {
         fclose( f );
-        return( -1 );
+        return -1 ;
     }
 
     fclose( f );
 
-    return( 0 );
+    return 0 ;
 }
 
 int main( int argc, char *argv[] )