usb: host: ehci-platform: Update brcm, xgs-iproc-ehci workaround

The original workaround was added prior to commit e4788edc ("USB:
EHCI: Add alias for Broadcom INSNREG"). Now that brcm_insnreg exists in
struct ehci_regs we can use that instead of having a local definition.
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Link: https://lore.kernel.org/r/20220215000813.1779032-1-chris.packham@alliedtelesis.co.nzSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/ehci-platform.c

@@ -43,7 +43,6 @@
 #define hcd_to_ehci_priv(h) ((struct ehci_platform_priv *)hcd_to_ehci(h)->priv)
 
 #define BCM_USB_FIFO_THRESHOLD	0x00800040
-#define bcm_iproc_insnreg01	hostpc[0]
 
 struct ehci_platform_priv {
 	struct clk *clks[EHCI_MAX_CLKS];
@@ -81,7 +80,7 @@ static int ehci_platform_reset(struct usb_hcd *hcd)
 
 	if (of_device_is_compatible(pdev->dev.of_node, "brcm,xgs-iproc-ehci"))
 		ehci_writel(ehci, BCM_USB_FIFO_THRESHOLD,
-			    &ehci->regs->bcm_iproc_insnreg01);
+			    &ehci->regs->brcm_insnreg[1]);
 
 	return 0;
 }