Fix error attribute(target("+crc")) is unknown

Task-number: QTBUG-61975
Change-Id: I0b1b55c0737dad485b5ace8e6eb7cb842589453d
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>

src/corelib/tools/qhash.cpp

@@ -144,7 +144,9 @@ static inline bool hasFastCrc32()
 }
 
 template <typename Char>
+#if defined(Q_PROCESSOR_ARM_64)
 QT_FUNCTION_TARGET(CRC32)
+#endif
 static uint crc32(const Char *ptr, size_t len, uint h)
 {
     // The crc32[whbd] instructions on Aarch64/Aarch32 calculate a 32-bit CRC32 checksum

src/corelib/tools/qsimd_p.h

@@ -326,7 +326,10 @@
 #endif
 // AArch64/ARM64
 #if defined(Q_PROCESSOR_ARM_V8) && defined(__ARM_FEATURE_CRC32)
+#if defined(Q_PROCESSOR_ARM_64)
+// only available on aarch64
 #define QT_FUNCTION_TARGET_STRING_CRC32      "+crc"
+#endif
 #  include <arm_acle.h>
 #endif