Staging: speakup: Add identifier name to function declaration arguments.

void (*read_buff_add) argument didn't have an identifier name,
adding a name to it like the rest of all functions' arguments.
Signed-off-by: Sam Muhammed <jane.pnx9@gmail.com>
Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Link: https://lore.kernel.org/r/b2a1ca962553194840d8cd2bf1f7d3174e3b1336.1585046066.git.jane.pnx9@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/speakup/spk_types.h

@@ -189,7 +189,7 @@ struct spk_synth {
 	void (*flush)(struct spk_synth *synth);
 	int (*is_alive)(struct spk_synth *synth);
 	int (*synth_adjust)(struct st_var_header *var);
-	void (*read_buff_add)(u_char);
+	void (*read_buff_add)(u_char c);
 	unsigned char (*get_index)(struct spk_synth *synth);
 	struct synth_indexing indexing;
 	int alive;