Updated to v4.4.1 kernel headers.

Small modifications needed to allow compilation with the new headers:

- Manually modify bionic/libc/kernel/uapi/asm-mips/asm/siginfo.h to
  remove the uapi from the include.
- PR_XXX defines are now available for mips, so remove the definition
  from linker_mips.cpp.

Bug: 23789423
Change-Id: I6dc8a03b012426d3a937db15cb24d3a50fab5a8c
diff --git a/libc/kernel/uapi/asm-mips/asm/sigcontext.h b/libc/kernel/uapi/asm-mips/asm/sigcontext.h
index 59870bc..2fc0229 100644
--- a/libc/kernel/uapi/asm-mips/asm/sigcontext.h
+++ b/libc/kernel/uapi/asm-mips/asm/sigcontext.h
@@ -21,6 +21,11 @@
 #include <linux/types.h>
 #include <asm/sgidefs.h>
 /* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
+#define USED_FP (1 << 0)
+#define USED_FR1 (1 << 1)
+#define USED_HYBRID_FPRS (1 << 2)
+#define USED_EXTCONTEXT (1 << 3)
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #if _MIPS_SIM == _MIPS_SIM_ABI32
 struct sigcontext {
   unsigned int sc_regmask;