Update to v4.19 kernel headers.

Test: Builds and boots.
Change-Id: I99a9ed79666e143b47f02ca4e59eed94f69b7e4a
(cherry picked from commit a981e2e52e2e95a65fa9c9b6fb16dcb4c83dd576)
diff --git a/libc/kernel/uapi/linux/pcitest.h b/libc/kernel/uapi/linux/pcitest.h
index e6c0264..c6112d0 100644
--- a/libc/kernel/uapi/linux/pcitest.h
+++ b/libc/kernel/uapi/linux/pcitest.h
@@ -24,4 +24,7 @@
 #define PCITEST_WRITE _IOW('P', 0x4, unsigned long)
 #define PCITEST_READ _IOW('P', 0x5, unsigned long)
 #define PCITEST_COPY _IOW('P', 0x6, unsigned long)
+#define PCITEST_MSIX _IOW('P', 0x7, int)
+#define PCITEST_SET_IRQTYPE _IOW('P', 0x8, int)
+#define PCITEST_GET_IRQTYPE _IO('P', 0x9)
 #endif