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-x86/asm/kvm_para.h b/libc/kernel/uapi/asm-x86/asm/kvm_para.h
index 0e4f2e0..47ecca9 100644
--- a/libc/kernel/uapi/asm-x86/asm/kvm_para.h
+++ b/libc/kernel/uapi/asm-x86/asm/kvm_para.h
@@ -31,6 +31,7 @@
 #define KVM_FEATURE_PV_UNHALT 7
 #define KVM_FEATURE_PV_TLB_FLUSH 9
 #define KVM_FEATURE_ASYNC_PF_VMEXIT 10
+#define KVM_FEATURE_PV_SEND_IPI 11
 #define KVM_HINTS_REALTIME 0
 #define KVM_FEATURE_CLOCKSOURCE_STABLE_BIT 24
 #define MSR_KVM_WALL_CLOCK 0x11