usb: musb: da8xx: Remove try_idle implementation from host-only mode

The idle_state is not meant for host-only mode. When the device acts as a
host, it fails to exit the idle state once entered. This prevents new
USB gadgets from being detected once plugged in.

Commit 032ec49f5351 ("usb: musb: drop useless board_mode usage") removed
a is_otg_enabled() check in the try_idle() that prevented from entering
idle_state. This was removed because at that time it was not possible to
select host-only mode with CONFIG_USB_MUSB_HOST so dual role was always
set.

Add #ifndef CONFIG_USB_MUSB_HOST around try_idle() callback to prevent
from entering idle_state when host-only mode has been selected.

Signed-off-by: Bastien Curutchet <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/musb/da8xx.c

···
 	spin_unlock_irqrestore(&musb->lock, flags);
 }
 
-static void da8xx_musb_try_idle(struct musb *musb, unsigned long timeout)
+static void __maybe_unused da8xx_musb_try_idle(struct musb *musb, unsigned long timeout)
 {
 	static unsigned long last_timer;
 
···
 	.disable	= da8xx_musb_disable,
 
 	.set_mode	= da8xx_musb_set_mode,
+
+#ifndef CONFIG_USB_MUSB_HOST
 	.try_idle	= da8xx_musb_try_idle,
+#endif
 
 	.set_vbus	= da8xx_musb_set_vbus,
 };