ARM: dts: Fix occasional boot hang for am3 usb

[ Upstream commit 9b6a51aa ]

With subtle timings changes, we can now sometimes get an external abort on
non-linefetch error booting am3 devices at sysc_reset(). This is because
of a missing reset delay needed for the usb target module.

Looks like we never enabled the delay earlier for am3, although a similar
issue was seen earlier with a similar usb setup for dm814x as described in
commit ebf24414 ("ARM: OMAP2+: Use srst_udelay for USB on dm814x").

Cc: stable@vger.kernel.org
Fixes: 0782e857

 ("ARM: dts: Probe am335x musb with ti-sysc")
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>