Update to v4.19 kernel headers.

Test: Builds and boots.
Change-Id: I99a9ed79666e143b47f02ca4e59eed94f69b7e4a
(cherry picked from commit a981e2e52e2e95a65fa9c9b6fb16dcb4c83dd576)
diff --git a/libc/kernel/uapi/asm-mips/asm/unistd.h b/libc/kernel/uapi/asm-mips/asm/unistd.h
index 76d7b81..e4dee2b 100644
--- a/libc/kernel/uapi/asm-mips/asm/unistd.h
+++ b/libc/kernel/uapi/asm-mips/asm/unistd.h
@@ -387,10 +387,12 @@
 #define __NR_pkey_alloc (__NR_Linux + 364)
 #define __NR_pkey_free (__NR_Linux + 365)
 #define __NR_statx (__NR_Linux + 366)
-#define __NR_Linux_syscalls 366
+#define __NR_rseq (__NR_Linux + 367)
+#define __NR_io_pgetevents (__NR_Linux + 368)
+#define __NR_Linux_syscalls 368
 #endif
 #define __NR_O32_Linux 4000
-#define __NR_O32_Linux_syscalls 366
+#define __NR_O32_Linux_syscalls 368
 #if _MIPS_SIM == _MIPS_SIM_ABI64
 #define __NR_Linux 5000
 #define __NR_read (__NR_Linux + 0)
@@ -719,10 +721,12 @@
 #define __NR_pkey_alloc (__NR_Linux + 324)
 #define __NR_pkey_free (__NR_Linux + 325)
 #define __NR_statx (__NR_Linux + 326)
-#define __NR_Linux_syscalls 326
+#define __NR_rseq (__NR_Linux + 327)
+#define __NR_io_pgetevents (__NR_Linux + 328)
+#define __NR_Linux_syscalls 328
 #endif
 #define __NR_64_Linux 5000
-#define __NR_64_Linux_syscalls 326
+#define __NR_64_Linux_syscalls 328
 #if _MIPS_SIM == _MIPS_SIM_NABI32
 #define __NR_Linux 6000
 #define __NR_read (__NR_Linux + 0)
@@ -1055,8 +1059,10 @@
 #define __NR_pkey_alloc (__NR_Linux + 328)
 #define __NR_pkey_free (__NR_Linux + 329)
 #define __NR_statx (__NR_Linux + 330)
-#define __NR_Linux_syscalls 330
+#define __NR_rseq (__NR_Linux + 331)
+#define __NR_io_pgetevents (__NR_Linux + 332)
+#define __NR_Linux_syscalls 332
 #endif
 #define __NR_N32_Linux 6000
-#define __NR_N32_Linux_syscalls 330
+#define __NR_N32_Linux_syscalls 332
 #endif