Fix missing asm/unistd_64.h error in local Android ARM64 builds

Modern Android NDKs strictly isolate architecture sysroots. The previous
inclusion of `<asm/unistd_64.h>` (an x86_64 header) inside an ARM64
block causes a fatal "file not found" error during compilation.

This CL updates jvm.cc to use the generic `<asm/unistd.h>` wrapper
instead, which correctly routes to the appropriate system call numbers
for the target architecture and resolves the build breakage.

Bug: b/502437863
Change-Id: I44c7162d4509c77b8698c533aa25460a5ae44298
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/464160
Owners-Override: Per Åhgren <peah@webrtc.org>
Auto-Submit: Per Åhgren <peah@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#47427}
diff --git a/sdk/android/src/jni/jvm.cc b/sdk/android/src/jni/jvm.cc
index fa87e1d..a2aa09e 100644
--- a/sdk/android/src/jni/jvm.cc
+++ b/sdk/android/src/jni/jvm.cc
@@ -24,7 +24,7 @@
 #include "third_party/jni_zero/jni_zero.h"
 
 #ifdef WEBRTC_ARCH_ARM64
-#include <asm/unistd_64.h>
+#include <asm/unistd.h>
 #endif
 
 namespace webrtc {