printk: rectify kernel-doc for prb_rec_init_wr()

The command 'find ./kernel/printk/ | xargs ./scripts/kernel-doc -none'
reported a mismatch with the kernel-doc of prb_rec_init_wr().

Rectify the kernel-doc, such that no issues remain for ./kernel/printk/.
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20210125081748.19903-1-lukas.bulwahn@gmail.com

kernel/printk/printk_ringbuffer.h

@@ -287,7 +287,7 @@ _DEFINE_PRINTKRB(name, descbits, avgtextbits, &_##name##_text[0])
 /* Writer Interface */
 
 /**
- * prb_rec_init_wd() - Initialize a buffer for writing records.
+ * prb_rec_init_wr() - Initialize a buffer for writing records.
  *
  * @r:             The record to initialize.
  * @text_buf_size: The needed text buffer size.