eth/r8152: modify rtl_clear_bp function

The original rtl_clear_bp() is used to clear the firmware of both
PLA and USB MCU. The new one could clear the firmware of PLA or
USB independently. It is unnecessary to clear firmware, if there
is no one to be updated.

Besides, clear the firmware by writing the relative registers in
bulk.

Signed-off-by: Hayes Wang <hayeswang@realtek.com>
diff --git a/drivers/usb/eth/r8152.h b/drivers/usb/eth/r8152.h
index 4daf4ee..710637d 100644
--- a/drivers/usb/eth/r8152.h
+++ b/drivers/usb/eth/r8152.h
@@ -95,16 +95,9 @@
 #define USB_MISC_0		0xd81a
 #define USB_AFE_CTRL2		0xd824
 #define USB_WDT11_CTRL		0xe43c
-#define USB_BP_BA		0xfc26
-#define USB_BP_0		0xfc28
-#define USB_BP_1		0xfc2a
-#define USB_BP_2		0xfc2c
-#define USB_BP_3		0xfc2e
-#define USB_BP_4		0xfc30
-#define USB_BP_5		0xfc32
-#define USB_BP_6		0xfc34
-#define USB_BP_7		0xfc36
-#define USB_BP_EN		0xfc38
+#define USB_BP_BA		PLA_BP_BA
+#define USB_BP(n)		(0xfc28 + 2 * (n))
+#define USB_BP_EN		PLA_BP_EN
 
 /* OCP Registers */
 #define OCP_ALDPS_CONFIG	0x2010