iio: accel: mma9551_core: wrong doc fixes

Fix docummentation for mma9553_read_* functions.

Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
Reported-by: Hartmut Knaack <knaack.h@gmx.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/accel/mma9551_core.c

@@ -374,7 +374,7 @@ EXPORT_SYMBOL(mma9551_read_status_word);
  * @app_id:	Application ID
  * @reg:	Application register
  * @len:	Length of array to read in bytes
- * @val:	Array of words to read
+ * @buf:	Array of words to read
  *
  * Read multiple configuration registers (word-sized registers).
  *
@@ -409,7 +409,7 @@ EXPORT_SYMBOL(mma9551_read_config_words);
  * @app_id:	Application ID
  * @reg:	Application register
  * @len:	Length of array to read in bytes
- * @val:	Array of words to read
+ * @buf:	Array of words to read
  *
  * Read multiple status registers (word-sized registers).
  *
@@ -444,7 +444,7 @@ EXPORT_SYMBOL(mma9551_read_status_words);
  * @app_id:	Application ID
  * @reg:	Application register
  * @len:	Length of array to write in bytes
- * @val:	Array of words to write
+ * @buf:	Array of words to write
  *
  * Write multiple configuration registers (word-sized registers).
  *