[net] e1000: Fix driver to be used on PA RISC C8000 workstations

The checksum field in the EEPROM on HPPA is really not a
checksum but a signature (0x16d6).  So allow 0x16d6 as the
matching checksum on HPPA systems.

This issue is present on longterm/stable kernels, I have
verified that this patch is applicable back to at least
2.6.32.y kernels.

CC: Guy Martin <redacted>
CC: Rolf Eike Beer <redacted>
CC: Matt Turner <mattst88@gmail.com>
Reported-by: Mikulas Patocka <redacted>
Signed-off-by: Jeff Kirsher <redacted>
Acked-by: Jesse Brandeburg <redacted>
---
 drivers/net/e1000/e1000_hw.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/drivers/net/e1000/e1000_hw.c b/drivers/net/e1000/e1000_hw.c
index 8545c7a..08c1ad5 100644
--- a/drivers/net/e1000/e1000_hw.c
+++ b/drivers/net/e1000/e1000_hw.c

@@ -4026,6 +4026,12 @@ s32 e1000_validate_eeprom_checksum(struct e1000_hw *hw)
 		checksum += eeprom_data;
 	}
 
+#ifdef __hppa__
+	/* This is a signature and not a checksum on HP c8000 */
+	if ((hw->subsystem_vendor_id == 0x103C) && (eeprom_data == 0x16d6))
+		return E1000_SUCCESS;
+
+#endif
 	if (checksum == (u16) EEPROM_SUM)
 		return E1000_SUCCESS;
 	else {

-- 
1.7.6