nvme: have nvme_init_identify set ctrl->cap

No need to use a stack cap variable.
Reviewed-by: Minwoo Im <minwoo.im.dev@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>

drivers/nvme/host/core.c

@@ -2562,7 +2562,6 @@ static int nvme_get_effects_log(struct nvme_ctrl *ctrl)
 int nvme_init_identify(struct nvme_ctrl *ctrl)
 {
 	struct nvme_id_ctrl *id;
-	u64 cap;
 	int ret, page_shift;
 	u32 max_hw_sectors;
 	bool prev_apst_enabled;
@@ -2573,15 +2572,15 @@ int nvme_init_identify(struct nvme_ctrl *ctrl)
 		return ret;
 	}
 
-	ret = ctrl->ops->reg_read64(ctrl, NVME_REG_CAP, &cap);
+	ret = ctrl->ops->reg_read64(ctrl, NVME_REG_CAP, &ctrl->cap);
 	if (ret) {
 		dev_err(ctrl->device, "Reading CAP failed (%d)\n", ret);
 		return ret;
 	}
-	page_shift = NVME_CAP_MPSMIN(cap) + 12;
+	page_shift = NVME_CAP_MPSMIN(ctrl->cap) + 12;
 
 	if (ctrl->vs >= NVME_VS(1, 1, 0))
-		ctrl->subsystem = NVME_CAP_NSSRC(cap);
+		ctrl->subsystem = NVME_CAP_NSSRC(ctrl->cap);
 
 	ret = nvme_identify_ctrl(ctrl, &id);
 	if (ret) {