at25: make input buffers of at25_*write() const

| drivers/misc/eeprom/at25.c:358: warning: assignment from incompatible pointer type
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/misc/eeprom/at25.c

@@ -140,7 +140,8 @@ at25_bin_read(struct kobject *kobj, struct bin_attribute *bin_attr,
 
 
 static ssize_t
-at25_ee_write(struct at25_data *at25, char *buf, loff_t off, size_t count)
+at25_ee_write(struct at25_data *at25, const char *buf, loff_t off,
+	      size_t count)
 {
 	ssize_t			status = 0;
 	unsigned		written = 0;
@@ -276,7 +277,7 @@ static ssize_t at25_mem_read(struct memory_accessor *mem, char *buf,
 	return at25_ee_read(at25, buf, offset, count);
 }
 
-static ssize_t at25_mem_write(struct memory_accessor *mem, char *buf,
+static ssize_t at25_mem_write(struct memory_accessor *mem, const char *buf,
 			  off_t offset, size_t count)
 {
 	struct at25_data *at25 = container_of(mem, struct at25_data, mem);