Update to v4.17.3 kernel headers.

Test: Builds, boots on a walleye.
Change-Id: I389d8b61ec00ea309e38d1b1a2e0dace48c21edb
diff --git a/libc/kernel/uapi/asm-mips/asm/hwcap.h b/libc/kernel/uapi/asm-mips/asm/hwcap.h
index 638017e..6151555 100644
--- a/libc/kernel/uapi/asm-mips/asm/hwcap.h
+++ b/libc/kernel/uapi/asm-mips/asm/hwcap.h
@@ -20,4 +20,5 @@
 #define _UAPI_ASM_HWCAP_H
 #define HWCAP_MIPS_R6 (1 << 0)
 #define HWCAP_MIPS_MSA (1 << 1)
+#define HWCAP_MIPS_CRC32 (1 << 2)
 #endif