Update to v5.15 kernel headers.

Kernel headers coming from:

Git: https://android.googlesource.com/kernel/common/
Branch: android-mainline
Tag: android-mainline-5.15

Test: Builds, and ran bionic unit tests on flame.
Change-Id: I86901ea6d89fb0f7384b90a47bef35d194083c24
diff --git a/libc/kernel/uapi/linux/ethtool.h b/libc/kernel/uapi/linux/ethtool.h
index 04a1d3d..5f9da4d 100644
--- a/libc/kernel/uapi/linux/ethtool.h
+++ b/libc/kernel/uapi/linux/ethtool.h
@@ -232,6 +232,8 @@
 enum ethtool_link_ext_substate_bad_signal_integrity {
   ETHTOOL_LINK_EXT_SUBSTATE_BSI_LARGE_NUMBER_OF_PHYSICAL_ERRORS = 1,
   ETHTOOL_LINK_EXT_SUBSTATE_BSI_UNSUPPORTED_RATE,
+  ETHTOOL_LINK_EXT_SUBSTATE_BSI_SERDES_REFERENCE_CLOCK_LOST,
+  ETHTOOL_LINK_EXT_SUBSTATE_BSI_SERDES_ALOS,
 };
 enum ethtool_link_ext_substate_cable_issue {
   ETHTOOL_LINK_EXT_SUBSTATE_CI_UNSUPPORTED_CABLE = 1,