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/if_ether.h b/libc/kernel/uapi/linux/if_ether.h
index 8405653..2890b36 100644
--- a/libc/kernel/uapi/linux/if_ether.h
+++ b/libc/kernel/uapi/linux/if_ether.h
@@ -123,6 +123,7 @@
 #define ETH_P_CAIF 0x00F7
 #define ETH_P_XDSA 0x00F8
 #define ETH_P_MAP 0x00F9
+#define ETH_P_MCTP 0x00FA
 #ifndef __UAPI_DEF_ETHHDR
 #define __UAPI_DEF_ETHHDR 1
 #endif