Hack: QSPIFlash: also remove _needs_fast_mode for macronix quirks

Completes e8674c3fc4c78946b6c7c3f38de23d7773733350

This avoids triggering MBED_ASSERT(_num_status_registers == 3); (only applies in debug mode)

Author: facchinm

components/storage/blockdevice/COMPONENT_QSPIF/QSPIFBlockDevice.cpp

@@ -1058,7 +1058,7 @@ int QSPIFBlockDevice::_handle_vendor_quirks()
             // 2. Require setting a "fast mode" bit in config register 2 to operate at higher clock rates
             // 3. Should never attempt to enable 4-byte addressing (it causes reads and writes to fail)
             tr_debug("Applying quirks for macronix");
-            _needs_fast_mode = true;
+            //_needs_fast_mode = true;
             _read_status_reg_2_inst = QSPIF_INST_RDCR;
             _attempt_4_byte_addressing = false;
             break;