[gdb/tdep] Fix mmap syscall mapping

There are a few spots where an mmap system call is mapped onto enum
gdb_syscall value gdb_sys_mmap2.

Strictly speaking, this is incorrect.

Fix this by mapping to enum gdb_syscall value gdb_old_mmap instead.

No functional changes: both gdb_old_mmap and gdb_sys_mmap2 are handled the
same in record_linux_system_call.

Tested by rebuilding on x86_64-linux.

gdb/aarch64-linux-tdep.c

diff --git a/gdb/aarch64-linux-tdep.c b/gdb/aarch64-linux-tdep.c
index 0b4ae7f..ec68ade 100644
--- a/gdb/aarch64-linux-tdep.c
+++ b/gdb/aarch64-linux-tdep.c
@@ -2275,7 +2275,7 @@ aarch64_canonicalize_syscall (enum aarch64_syscall syscall_number)
       SYSCALL_MAP (clone);
       SYSCALL_MAP (execve);
 
-      SYSCALL_MAP_RENAME (mmap, gdb_sys_mmap2);
+      SYSCALL_MAP_RENAME (mmap, gdb_old_mmap);
 
       SYSCALL_MAP (fadvise64);
       SYSCALL_MAP (swapon);

gdb/amd64-linux-tdep.c

diff --git a/gdb/amd64-linux-tdep.c b/gdb/amd64-linux-tdep.c
index e290d2c..69e2054 100644
--- a/gdb/amd64-linux-tdep.c
+++ b/gdb/amd64-linux-tdep.c
@@ -412,7 +412,7 @@ amd64_canonicalize_syscall (enum amd64_syscall syscall_number)
 
   case amd64_sys_mmap:
   case amd64_x32_sys_mmap:
-    return gdb_sys_mmap2;
+    return gdb_old_mmap;
 
   case amd64_sys_mprotect:
   case amd64_x32_sys_mprotect:

gdb/loongarch-linux-tdep.c

diff --git a/gdb/loongarch-linux-tdep.c b/gdb/loongarch-linux-tdep.c
index bd42d09..949327d 100644
--- a/gdb/loongarch-linux-tdep.c
+++ b/gdb/loongarch-linux-tdep.c
@@ -812,7 +812,7 @@ loongarch_canonicalize_syscall (enum loongarch_syscall syscall_number)
       SYSCALL_MAP (clone);
       SYSCALL_MAP (execve);
 
-      SYSCALL_MAP_RENAME (mmap, gdb_sys_mmap2);
+      SYSCALL_MAP_RENAME (mmap, gdb_old_mmap);
 
       SYSCALL_MAP (fadvise64);
       SYSCALL_MAP (swapon);