e1000e: make lost bits explicit

For more than 15 years this code has passed in a request for a page and
masked off that page when read/writing. This code has been here forever,
but FIELD_PREP finds the bug when converted to use it. Change the code
to do exactly the same thing but allow the conversion to FIELD_PREP in a
later patch. To make it clear what we lost when making this change I
left a comment, but there is no point to change the code to generate a
correct sequence at this point.

This is not a Fixes tagged patch on purpose because it doesn't change
the binary output.

Reviewed-by: Marcin Szycik <[e-mail]>
Signed-off-by: Jesse Brandeburg <[e-mail]>
Signed-off-by: Tony Nguyen <[e-mail]>

drivers/net/ethernet/intel/e1000e/80003es2lan.c

···
 	 * iteration and increase the max iterations when
 	 * polling the phy; this fixes erroneous timeouts at 10Mbps.
 	 */
-	ret_val = e1000_write_kmrn_reg_80003es2lan(hw, GG82563_REG(0x34, 4),
-						   0xFFFF);
+	/* these next three accesses were always meant to use page 0x34 using
+	 * GG82563_REG(0x34, N) but never did, so we've just corrected the call
+	 * to not drop bits
+	 */
+	ret_val = e1000_write_kmrn_reg_80003es2lan(hw, 4, 0xFFFF);
 	if (ret_val)
 		return ret_val;
-	ret_val = e1000_read_kmrn_reg_80003es2lan(hw, GG82563_REG(0x34, 9),
-						  &reg_data);
+	ret_val = e1000_read_kmrn_reg_80003es2lan(hw, 9, &reg_data);
 	if (ret_val)
 		return ret_val;
 	reg_data |= 0x3F;
-	ret_val = e1000_write_kmrn_reg_80003es2lan(hw, GG82563_REG(0x34, 9),
-						   reg_data);
+	ret_val = e1000_write_kmrn_reg_80003es2lan(hw, 9, reg_data);
 	if (ret_val)
 		return ret_val;
 	ret_val =