USB: isp1760: Add a delay before reading the SKIPMAP registers in isp1760-hcd.c

The data read from the SKIPMAP registers is not immediately available
after writing and the driver panics when a packet is enqueued from the
interrupt handler. This patch adds an ndelay(195) before these registers
are read (delay value mentioned in section 15.1.1.3 of the ISP1760 data
sheet).

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>