Update to v5.5 kernel headers.

Kernel headers coming from:

Git: https://android.googlesource.com/kernel/common/
Branch: android-mainline
Tag: android-mainline-5.5

Test: Boots on walleye.
Test: Ran bionic-unit-tests on walleye.
Test: Boots on cuttlefish.
Test: Ran bionic-unit-tests on cuttlefish.
Change-Id: I57387d3c31e0ba5ad125ffe291cecf365c7b374e
diff --git a/libc/kernel/uapi/linux/ethtool.h b/libc/kernel/uapi/linux/ethtool.h
index 28209e3..cc951d1 100644
--- a/libc/kernel/uapi/linux/ethtool.h
+++ b/libc/kernel/uapi/linux/ethtool.h
@@ -610,6 +610,11 @@
   ETHTOOL_LINK_MODE_200000baseCR4_Full_BIT = 66,
   ETHTOOL_LINK_MODE_100baseT1_Full_BIT = 67,
   ETHTOOL_LINK_MODE_1000baseT1_Full_BIT = 68,
+  ETHTOOL_LINK_MODE_400000baseKR8_Full_BIT = 69,
+  ETHTOOL_LINK_MODE_400000baseSR8_Full_BIT = 70,
+  ETHTOOL_LINK_MODE_400000baseLR8_ER8_FR8_Full_BIT = 71,
+  ETHTOOL_LINK_MODE_400000baseDR8_Full_BIT = 72,
+  ETHTOOL_LINK_MODE_400000baseCR8_Full_BIT = 73,
   __ETHTOOL_LINK_MODE_MASK_NBITS
 };
 #define __ETHTOOL_LINK_MODE_LEGACY_MASK(base_name) (1UL << (ETHTOOL_LINK_MODE_ ##base_name ##_BIT))
@@ -689,6 +694,7 @@
 #define SPEED_56000 56000
 #define SPEED_100000 100000
 #define SPEED_200000 200000
+#define SPEED_400000 400000
 #define SPEED_UNKNOWN - 1
 #define DUPLEX_HALF 0x00
 #define DUPLEX_FULL 0x01