Revert "Make system property reads wait-free"

This reverts commit 0cf90556de2bde53a1957c5946036b2fe2e4e429.

Reason for revert: Device boot failures - 144355953

Change-Id: Icd4fc8c7a1d06d688a6d37e6f1c1aa45563f711b
diff --git a/libc/bionic/system_property_api.cpp b/libc/bionic/system_property_api.cpp
index a641f12..051bc4c 100644
--- a/libc/bionic/system_property_api.cpp
+++ b/libc/bionic/system_property_api.cpp
@@ -100,13 +100,7 @@
 
 __BIONIC_WEAK_FOR_NATIVE_BRIDGE
 uint32_t __system_property_serial(const prop_info* pi) {
-  // N.B. a previous version of this function was much heavier-weight
-  // and enforced acquire semantics, so give our load here acquire
-  // semantics just in case somebody depends on
-  // __system_property_serial enforcing memory order, e.g., in case
-  // someone spins on the result of this function changing before
-  // loading some value.
-  return atomic_load_explicit(&pi->serial, memory_order_acquire);
+  return system_properties.Serial(pi);
 }
 
 __BIONIC_WEAK_FOR_NATIVE_BRIDGE