cmd: qfw: rename qemu_fw_cfg.[c|h] to qfw.[c|h]

Make file names consistent with CONFIG_QFW and CONFIG_CMD_QFW

Signed-off-by: Miao Yan <yanmiaobest@gmail.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index fa53700..c40f6b5 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -142,6 +142,6 @@
 	bool
 	help
 	  Hidden option to enable QEMU fw_cfg interface. This will be selected by
-	  either CONFIG_CMD_QEMU_FW_CFG or CONFIG_GENERATE_ACPI_TABLE.
+	  either CONFIG_CMD_QFW or CONFIG_GENERATE_ACPI_TABLE.
 
 endmenu