ssb: Use true and false for bool variable

Fix the following coccicheck warnings:

./include/linux/ssb/ssb_driver_gige.h:89:8-9: WARNING: return of 0/1 in
function 'ssb_gige_one_dma_at_once' with return type bool.

./include/linux/ssb/ssb_driver_gige.h:79:8-9: WARNING: return of 0/1 in
function 'ssb_gige_have_roboswitch' with return type bool.

./include/linux/ssb/ssb_driver_gige.h:182:8-9: WARNING: return of 0/1 in
function 'ssb_gige_must_flush_posted_writes' with return type bool.

./include/linux/ssb/ssb_driver_gige.h:178:8-9: WARNING: return of 0/1 in
function 'ssb_gige_one_dma_at_once' with return type bool.

./include/linux/ssb/ssb_driver_gige.h:174:8-9: WARNING: return of 0/1 in
function 'ssb_gige_have_roboswitch' with return type bool.

./include/linux/ssb/ssb_driver_gige.h:170:8-9: WARNING: return of 0/1 in
function 'ssb_gige_is_rgmii' with return type bool.

./include/linux/ssb/ssb_driver_gige.h:162:8-9: WARNING: return of 0/1 in
function 'pdev_is_ssb_gige_core' with return type bool.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Acked-by: Michael Büsch <m@bues.ch>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/1612508199-92282-1-git-send-email-jiapeng.chong@linux.alibaba.com

include/linux/ssb/ssb_driver_gige.h

@@ -76,7 +76,7 @@ static inline bool ssb_gige_have_roboswitch(struct pci_dev *pdev)
 	if (dev)
 		return !!(dev->dev->bus->sprom.boardflags_lo &
 			  SSB_GIGE_BFL_ROBOSWITCH);
-	return 0;
+	return false;
 }
 
 /* Returns whether we can only do one DMA at once. */
@@ -86,7 +86,7 @@ static inline bool ssb_gige_one_dma_at_once(struct pci_dev *pdev)
 	if (dev)
 		return ((dev->dev->bus->chip_id == 0x4785) &&
 			(dev->dev->bus->chip_rev < 2));
-	return 0;
+	return false;
 }
 
 /* Returns whether we must flush posted writes. */
@@ -159,7 +159,7 @@ static inline void ssb_gige_exit(void)
 
 static inline bool pdev_is_ssb_gige_core(struct pci_dev *pdev)
 {
-	return 0;
+	return false;
 }
 static inline struct ssb_gige * pdev_to_ssb_gige(struct pci_dev *pdev)
 {
@@ -167,19 +167,19 @@ static inline struct ssb_gige * pdev_to_ssb_gige(struct pci_dev *pdev)
 }
 static inline bool ssb_gige_is_rgmii(struct pci_dev *pdev)
 {
-	return 0;
+	return false;
 }
 static inline bool ssb_gige_have_roboswitch(struct pci_dev *pdev)
 {
-	return 0;
+	return false;
 }
 static inline bool ssb_gige_one_dma_at_once(struct pci_dev *pdev)
 {
-	return 0;
+	return false;
 }
 static inline bool ssb_gige_must_flush_posted_writes(struct pci_dev *pdev)
 {
-	return 0;
+	return false;
 }
 static inline int ssb_gige_get_macaddr(struct pci_dev *pdev, u8 *macaddr)
 {