usb: bdc: Fix misleading register names

The BDC endpoint status registers 0-7 were originally each going
to be an array of regsiters. This was later changed to being a
single register. The register definitions are being changed from:
"#define BDC_EPSTS0(n)  (0x60 + (n * 0x10))"
to
"#define BDC_EPSTS0	0x60"
to reflect this change and to avoid future coding mistakes.

Signed-off-by: Al Cooper <alcooperx@gmail.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>