linux-user: Don't use UID16 on AArch64

The AArch64 kernel defines its __kernel_uid_t type as 32 bits, unlike
32 bit ARM, so don't enable our 16-bit UID wrapper handling.

Signed-off-by: Andreas Schwab <schwab@suse.de>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>

linux-user/syscall_defs.h

diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
index 3c8869e..d55f396 100644
--- a/linux-user/syscall_defs.h
+++ b/linux-user/syscall_defs.h
@@ -53,7 +53,8 @@
 #define TARGET_IOC_NRBITS	8
 #define TARGET_IOC_TYPEBITS	8
 
-#if defined(TARGET_I386) || defined(TARGET_ARM) || defined(TARGET_SPARC) \
+#if defined(TARGET_I386) || (defined(TARGET_ARM) && defined(TARGET_ABI32)) \
+    || defined(TARGET_SPARC) \
     || defined(TARGET_M68K) || defined(TARGET_SH4) || defined(TARGET_CRIS)
     /* 16 bit uid wrappers emulation */
 #define USE_UID16