mtd: spi-nor: replace unnecessary div64_u64() with div_u64()

Both occurrences of div64_u64() just have a u8 or u32 divisor. Use
div_u64() instead. Many 32 bit architectures can optimize this variant
better than a full 64 bit divide.
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/9ba7f4e6-2b8b-44a3-9cac-9ed6e50f1700@moroto.mountain/Signed-off-by: Michael Walle <mwalle@kernel.org>
Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
[pratyush@kernel.org: touched up commit message]
Signed-off-by: Pratyush Yadav <pratyush@kernel.org>
Link: https://lore.kernel.org/r/20240429121113.803703-1-mwalle@kernel.org

drivers/mtd/spi-nor/core.c

@@ -2893,7 +2893,7 @@ static int spi_nor_late_init_params(struct spi_nor *nor)
 		spi_nor_init_default_locking_ops(nor);
 
 	if (params->n_banks > 1)
-		params->bank_size = div64_u64(params->size, params->n_banks);
+		params->bank_size = div_u64(params->size, params->n_banks);
 
 	return 0;
 }
@@ -3406,7 +3406,7 @@ static int spi_nor_set_mtd_eraseregions(struct spi_nor *nor)
 			return -EINVAL;
 
 		mtd_region[i].erasesize = erasesize;
-		mtd_region[i].numblocks = div64_ul(region[i].size, erasesize);
+		mtd_region[i].numblocks = div_u64(region[i].size, erasesize);
 		mtd_region[i].offset = region[i].offset;
 	}