usb_session: increase default ram quota

The new usb_host driver for PC by default needs more RAM quota in contrast
to the old one. To minor warnings and repeated attempts to open a USB
session from a client, this commit increases the default RAM quota by one
page.

Ref genodelabs#4416

repos/os/include/usb_session/connection.h

@@ -35,7 +35,7 @@ struct Usb::Connection : Genode::Connection<Session>, Session_client
 		Genode::Connection<Session>(env,
 			session(env.parent(),
 			        "ram_quota=%ld, cap_quota=%ld, tx_buf_size=%ld, label=\"%s\"",
-			        3 * 4096 + tx_buf_size, CAP_QUOTA, tx_buf_size, label)),
+			        4 * 4096 + tx_buf_size, CAP_QUOTA, tx_buf_size, label)),
 		Session_client(cap(), *tx_block_alloc, env.rm(), sigh_state_changed)
 	{ }
 };