Turn off integer overflow UBSAN checks for hash functions

These functions intentionally overflows integers. The upcoming compiler
update, clang-r522817, will start complaining about these overflows.

Test: boot with new compiler
Bug: 325934863
Change-Id: I5e83a55e880f4e78a7de5a7b01ee99e64f601ca7
diff --git a/libs/ui/DisplayIdentification.cpp b/libs/ui/DisplayIdentification.cpp
index a45ffe1..82e5427 100644
--- a/libs/ui/DisplayIdentification.cpp
+++ b/libs/ui/DisplayIdentification.cpp
@@ -47,6 +47,7 @@
     return val ^ (val >> 47);
 }
 
+__attribute__((no_sanitize("unsigned-integer-overflow")))
 uint64_t hash64Len16(uint64_t u, uint64_t v) {
     constexpr uint64_t kMul = 0x9ddfea08eb382d69;
     uint64_t a = (u ^ v) * kMul;
@@ -57,6 +58,7 @@
     return b;
 }
 
+__attribute__((no_sanitize("unsigned-integer-overflow")))
 uint64_t hash64Len0To16(const char* s, uint64_t len) {
     constexpr uint64_t k2 = 0x9ae16a3b2f90404f;
     constexpr uint64_t k3 = 0xc949d7c7509e6557;
@@ -401,4 +403,4 @@
     return hash64Len0To16(sv.data(), len);
 }
 
-} // namespace android
\ No newline at end of file
+} // namespace android