ath9k: trivial: change spectral relayfs buffering

The spectral data provided via relay-fs introduces a buffering
latency given by the subbuf_size. To meet the requirements for
delay-sensitive applications (like real-time spectral plotter),
reduce subbuf_size and increase n_subbufs.
Signed-off-by: Zefir Kurtisi <zefir.kurtisi@neratec.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/debug.c

@@ -2072,7 +2072,7 @@ int ath9k_init_debug(struct ath_hw *ah)
 			    &fops_modal_eeprom);
 	sc->rfs_chan_spec_scan = relay_open("spectral_scan",
 					    sc->debug.debugfs_phy,
-					    262144, 4, &rfs_spec_scan_cb,
+					    1024, 256, &rfs_spec_scan_cb,
 					    NULL);
 	debugfs_create_file("spectral_scan_ctl", S_IRUSR | S_IWUSR,
 			    sc->debug.debugfs_phy, sc,