ata: libata: Cleanup inline DMA helper functions

Simplify the inline DMA helper functions ata_using_mwdma(),
ata_using_udma() and ata_dma_enabled() to directly return as a boolean
the result of their test condition.
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Tested-by: Chia-Lin Kao (AceLan) <acelan.kao@canonical.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>

include/linux/libata.h

@@ -1886,23 +1886,21 @@ static inline unsigned long ata_deadline(unsigned long from_jiffies,
    change in future hardware and specs, secondly 0xFF means 'no DMA' but is
    > UDMA_0. Dyma ddreigiau */
 
-static inline int ata_using_mwdma(struct ata_device *adev)
+static inline bool ata_using_mwdma(struct ata_device *adev)
 {
-	if (adev->dma_mode >= XFER_MW_DMA_0 && adev->dma_mode <= XFER_MW_DMA_4)
-		return 1;
-	return 0;
+	return adev->dma_mode >= XFER_MW_DMA_0 &&
+		adev->dma_mode <= XFER_MW_DMA_4;
 }
 
-static inline int ata_using_udma(struct ata_device *adev)
+static inline bool ata_using_udma(struct ata_device *adev)
 {
-	if (adev->dma_mode >= XFER_UDMA_0 && adev->dma_mode <= XFER_UDMA_7)
-		return 1;
-	return 0;
+	return adev->dma_mode >= XFER_UDMA_0 &&
+		adev->dma_mode <= XFER_UDMA_7;
 }
 
-static inline int ata_dma_enabled(struct ata_device *adev)
+static inline bool ata_dma_enabled(struct ata_device *adev)
 {
-	return (adev->dma_mode == 0xFF ? 0 : 1);
+	return adev->dma_mode != 0xFF;
 }
 
 /**************************************************************************