ALSA: hdsp: Make the firmware loading ioctl a bit more readable

The firmware loading ioctl that is implemented for hdsp hwdep device
takes the reference of the address pointer, hence the current code is
rather confusing.  Also, due to the recent change in uapi header,
sparse also complains about the cast.

This patch tries to improve the readability by converting the
straightforward copy_from_user of the whole struct (which contains
only the pointer).

Fixes: d63e63d4 ("ALSA: hdsp: Make uapi/hdsp.h compilable again")
Link: https://lore.kernel.org/r/20200202090724.18232-2-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/rme9652/hdsp.c

@@ -4802,7 +4802,7 @@ static int snd_hdsp_hwdep_ioctl(struct snd_hwdep *hw, struct file *file, unsigne
 		break;
 	}
 	case SNDRV_HDSP_IOCTL_UPLOAD_FIRMWARE: {
-		struct hdsp_firmware __user *firmware;
+		struct hdsp_firmware firmware;
 		u32 __user *firmware_data;
 		int err;
 
@@ -4815,10 +4815,9 @@ static int snd_hdsp_hwdep_ioctl(struct snd_hwdep *hw, struct file *file, unsigne
 
 		dev_info(hdsp->card->dev,
 			 "initializing firmware upload\n");
-		firmware = (struct hdsp_firmware __user *)argp;
-
-		if (get_user(firmware_data, (__force void __user **)&firmware->firmware_data))
+		if (copy_from_user(&firmware, argp, sizeof(firmware)))
 			return -EFAULT;
+		firmware_data = (u32 __user *)firmware.firmware_data;
 
 		if (hdsp_check_for_iobox (hdsp))
 			return -EIO;