mtd: rawnand: omap: Fix kernel doc warning on 'calcuate' typo

Fix a trivial typo which is reported after enabling W=1 level of warnings:

  drivers/mtd/nand/raw/omap2.c:927: warning: expecting prototype
    for omap_calcuate_ecc(). Prototype was for omap_calculate_ecc() instead
Signed-off-by: NVladimir Molokov <vladimir@molokov.se>
Signed-off-by: NMiquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210801205909.7102-1-vladimir@molokov.se

drivers/mtd/nand/raw/omap2.c

@@ -911,7 +911,7 @@ static int omap_correct_data(struct nand_chip *chip, u_char *dat,
 }
 
 /**
- * omap_calcuate_ecc - Generate non-inverted ECC bytes.
+ * omap_calculate_ecc - Generate non-inverted ECC bytes.
  * @chip: NAND chip object
  * @dat: The pointer to data on which ecc is computed
  * @ecc_code: The ecc_code buffer