USB: gadget: f_mass_storage: get rid of DEVICE_ATTR() usage

The last holdout in the drivers/usb/* tree using DEVICE_ATTR() is the
f_mass_storage driver, so move it to use DEVICE_ATTR_RW() instead.  The
mode is overridden in the is_visible callback to set it properly
depending on if this is a cdrom or removable device.

Cc: Felipe Balbi <balbi@kernel.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Maxim Devaev <mdevaev@gmail.com>
Cc: Wesley Cheng <quic_wcheng@quicinc.com>
Cc: Neal Liu <neal_liu@aspeedtech.com>
Cc: Roger Quadros <roger.quadros@nokia.com>
Cc: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Cc: Cai Huoqing <cai.huoqing@linux.dev>
Link: https://lore.kernel.org/r/20220810123656.3637104-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/gadget/function/f_mass_storage.c

@@ -2662,11 +2662,16 @@ static ssize_t forced_eject_store(struct device *dev,
 }
 
 static DEVICE_ATTR_RW(nofua);
-/* mode wil be set in fsg_lun_attr_is_visible() */
-static DEVICE_ATTR(ro, 0, ro_show, ro_store);
-static DEVICE_ATTR(file, 0, file_show, file_store);
 static DEVICE_ATTR_WO(forced_eject);
 
+/*
+ * Mode of the ro and file attribute files will be overridden in
+ * fsg_lun_dev_is_visible() depending on if this is a cdrom, or if it is a
+ * removable device.
+ */
+static DEVICE_ATTR_RW(ro);
+static DEVICE_ATTR_RW(file);
+
 /****************************** FSG COMMON ******************************/
 
 static void fsg_lun_release(struct device *dev)