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/asm-arm/asm/unistd.h b/libc/kernel/uapi/asm-arm/asm/unistd.h
index a602321..8bb0f58 100644
--- a/libc/kernel/uapi/asm-arm/asm/unistd.h
+++ b/libc/kernel/uapi/asm-arm/asm/unistd.h
@@ -19,6 +19,7 @@
 #ifndef _UAPI__ASM_ARM_UNISTD_H
 #define _UAPI__ASM_ARM_UNISTD_H
 #define __NR_OABI_SYSCALL_BASE 0x900000
+#define __NR_SYSCALL_MASK 0x0fffff
 #define __NR_SYSCALL_BASE 0
 #include <asm/unistd-eabi.h>
 #define __NR_sync_file_range2 __NR_arm_sync_file_range