USB: gadget: function: remove redundant initialization of 'tv_nexus'

Pointer tv_nexus is being initialized a value and this is never read
and is later being updated with the same value. Remove the redundant
initialization so that the assignment to tv_nexus is performed later
and more local to when it is being read.

Cleans up clang warning:
drivers/usb/gadget/function/f_tcm.c:1097:25: warning: Value stored to
'tv_nexus' during its initialization is never read
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/gadget/function/f_tcm.c

@@ -1094,7 +1094,7 @@ static int usbg_submit_command(struct f_uas *fu,
 	struct command_iu *cmd_iu = cmdbuf;
 	struct usbg_cmd *cmd;
 	struct usbg_tpg *tpg = fu->tpg;
-	struct tcm_usbg_nexus *tv_nexus = tpg->tpg_nexus;
+	struct tcm_usbg_nexus *tv_nexus;
 	u32 cmd_len;
 	u16 scsi_tag;