cfi_flash: reset timer in flash status check

This patch adds reset_timer() before the flash status check
waiting loop.

Since the timer is basically running asynchronous to the cfi
code, it is possible to call get_timer(0), then only a few
_SYSCLK_ cycles later an interrupt is generated. This causes
timeout even though much less time has elapsed. So the timer
period registers should be reset before get_timer(0) is
called.

There is similar usage in nand_base.c.

Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/drivers/mtd/cfi_flash.c b/drivers/mtd/cfi_flash.c
index d0240f5..3267c5d 100644
--- a/drivers/mtd/cfi_flash.c
+++ b/drivers/mtd/cfi_flash.c
@@ -544,6 +544,7 @@
 #endif
 
 	/* Wait for command completion */
+	reset_timer();
 	start = get_timer (0);
 	while (flash_is_busy (info, sector)) {
 		if (get_timer (start) > tout) {
@@ -630,6 +631,7 @@
 #endif
 
 	/* Wait for command completion */
+	reset_timer();
 	start = get_timer(0);
 	while (1) {
 		switch (info->portwidth) {