Reduce the size of used constant in ssl_tls.c

Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 0a763f4..89ac9b4 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -56,7 +56,7 @@
 #include "mbedtls/oid.h"
 #endif
 
-#define PROPER_HS_FRAGMENT 0x75555555
+#define PROPER_HS_FRAGMENT 0x75
 
 #if defined(MBEDTLS_SSL_TRANSFORM_OPTIMIZE_CIPHERS)
 static int mbedtls_ssl_switch_key( mbedtls_ssl_transform *transform,