staging: dwc2: fix off-by-one in check for max_packet_count parameter

Previously, the max_packet_count could be set to 1 << x, where x is the
number of bits available (width + 4 in the code). Since 1 << x requires
x + 1 bits to represent, this will not work. The real maximum value is
(1 << x) - 1. This value is already used the default when the set value
is invalid, but the upper limit for the set value was off-by-one.

This change makes the check the same as the one for max_transfer_size,
which was already correct.
Signed-off-by: Matthijs Kooijman <matthijs@stdin.nl>
Acked-by: Paul Zimmerman <paulz@synopsys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/dwc2/core.c

@@ -2209,7 +2209,7 @@ int dwc2_set_param_max_packet_count(struct dwc2_hsotg *hsotg, int val)
 		    GHWCFG3_PACKET_SIZE_CNTR_WIDTH_MASK >>
 				GHWCFG3_PACKET_SIZE_CNTR_WIDTH_SHIFT;
 
-	if (val < 15 || val > (1 << (width + 4)))
+	if (val < 15 || val >= (1 << (width + 4)))
 		valid = 0;
 
 	if (!valid) {