Fix sloppy wording around stricly less-than vs less or equal

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/library/net_sockets.c b/library/net_sockets.c
index 375434a..ad1ac13 100644
--- a/library/net_sockets.c
+++ b/library/net_sockets.c
@@ -466,9 +466,9 @@
         return( MBEDTLS_ERR_NET_INVALID_CONTEXT );
 
     /* A limitation of select() is that it only works with file descriptors
-     * up to FD_SETSIZE. This is a limitation of the fd_set type. Error out
-     * early, because attempting to call FD_SET on a large file descriptor
-     * is a buffer overflow on typical platforms. */
+     * that are strictly less than FD_SETSIZE. This is a limitation of the
+     * fd_set type. Error out early, because attempting to call FD_SET on a
+     * large file descriptor is a buffer overflow on typical platforms. */
     if( fd >= FD_SETSIZE )
         return( MBEDTLS_ERR_NET_POLL_FAILED );
 
@@ -592,9 +592,9 @@
         return( MBEDTLS_ERR_NET_INVALID_CONTEXT );
 
     /* A limitation of select() is that it only works with file descriptors
-     * up to FD_SETSIZE. This is a limitation of the fd_set type. Error out
-     * early, because attempting to call FD_SET on a large file descriptor
-     * is a buffer overflow on typical platforms. */
+     * that are strictly less than FD_SETSIZE. This is a limitation of the
+     * fd_set type. Error out early, because attempting to call FD_SET on a
+     * large file descriptor is a buffer overflow on typical platforms. */
     if( fd >= FD_SETSIZE )
         return( MBEDTLS_ERR_NET_POLL_FAILED );