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/ecdsa.c b/programs/pkey/ecdsa.c
index 6b6e951..293bfba 100644
--- a/programs/pkey/ecdsa.c
+++ b/programs/pkey/ecdsa.c
@@ -81,7 +81,7 @@
     size_t len;
 
     if( mbedtls_ecp_point_write_binary( &key->MBEDTLS_PRIVATE(grp), &key->MBEDTLS_PRIVATE(Q),
-                MBEDTLS_ECP_PF_UNCOMPRESSED, &len, buf, sizeof buf ) != 0 )
+                MBEDTLS_ECP_PF_UNCOMPRESSED, &len, buf, sizeof(buf) ) != 0 )
     {
         mbedtls_printf("internal error\n");
         return;