UPSTREAM: usb: dwc3: debugfs: fix regdump offset

UPSTREAM: usb: dwc3: debugfs: fix regdump offset

As with dwc_readl/writel, the global registers are specified as
offsets starting from the beginning of the xHCI address space,
but the memory region pointed to by dwc->regs already maps to
the start of the global addresses. Fix by offsetting each of the
regs relative to DWC3_GLOBALS_REGS_START.

Signed-off-by: Jack Pham <jackp@codeaurora.org>
Signed-off-by: Felipe Balbi <balbi@ti.com>
(cherry picked from commit 1604c1e760119ab3fe9f71679ebaeb058d3d8ae1)
Cherry pick from Linus' tree, applied cleanly

BUG=chromium:229725
TEST='cat /sys/kernel/debug/dwc3.0/regdump' should not crash on Snow.

Change-Id: Ic58153b9c3f4135355094a5dc49ad0fabb2fcd25
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/48554
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>