remoteproc: Drop unnecessary NULL check

rproc_alloc() will make sure that the "firmware" pointer is either a
driver supplied value or pointing to a generated firmware filename, it
can't be NULL. So drop the extra check in the rproc_boot() path.
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

drivers/remoteproc/remoteproc_core.c

@@ -1034,13 +1034,6 @@ static int __rproc_boot(struct rproc *rproc, bool wait)
 		return ret;
 	}
 
-	/* loading a firmware is required */
-	if (!rproc->firmware) {
-		dev_err(dev, "%s: no firmware to load\n", __func__);
-		ret = -EINVAL;
-		goto unlock_mutex;
-	}
-
 	/* prevent underlying implementation from being removed */
 	if (!try_module_get(dev->parent->driver->owner)) {
 		dev_err(dev, "%s: can't get owner\n", __func__);