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/arch/x86/cpu/qemu/acpi_table.c b/arch/x86/cpu/qemu/acpi_table.c
index b17fa03..5bb1756 100644
--- a/arch/x86/cpu/qemu/acpi_table.c
+++ b/arch/x86/cpu/qemu/acpi_table.c
@@ -8,7 +8,7 @@
 #include <command.h>
 #include <errno.h>
 #include <malloc.h>
-#include <qemu_fw_cfg.h>
+#include <qfw.h>
 #include <asm/io.h>
 #include <asm/tables.h>
 #include <asm/e820.h>