treewide: replace with error() with pr_err()

U-Boot widely uses error() as a bit noisier variant of printf().

This macro causes name conflict with the following line in
include/linux/compiler-gcc.h:

  # define __compiletime_error(message) __attribute__((error(message)))

This prevents us from using __compiletime_error(), and makes it
difficult to fully sync BUILD_BUG macros with Linux.  (Notice
Linux's BUILD_BUG_ON_MSG is implemented by using compiletime_assert().)

Let's convert error() into now treewide-available pr_err().

Done with the help of Coccinelle, excluing tools/ directory.

The semantic patch I used is as follows:

// <smpl>
@@@@
-error
+pr_err
 (...)
// </smpl>

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
[trini: Re-run Coccinelle]
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/drivers/power/regulator/fixed.c b/drivers/power/regulator/fixed.c
index 35c2922..97b4a98 100644
--- a/drivers/power/regulator/fixed.c
+++ b/drivers/power/regulator/fixed.c
@@ -117,7 +117,7 @@
 
 	ret = dm_gpio_set_value(&dev_pdata->gpio, enable);
 	if (ret) {
-		error("Can't set regulator : %s gpio to: %d\n", dev->name,
+		pr_err("Can't set regulator : %s gpio to: %d\n", dev->name,
 		      enable);
 		return ret;
 	}