scsi: pm80xx: Increase reserved tags from 8 to 128

Increase the number of reserved tags to prevent command processing failures
when the driver is under stress. 8 reserved tags are quickly getting all
used up leading to errors when command completions are delayed.

The driver needs ~512 ccbs/tags for maximum I/O utilization:

16 (max disks) * 32 (max SATA queue depth) = ~512 ccbs/tags.

By reserving 128 tags the driver will still have plenty of tags/ccbs left:

1024 (max ccbs) - 128 (reserved slot) = 896 tags/ccbs left.

Signed-off-by: Igor Pylypiv <[e-mail]>
Signed-off-by: Salomon Dushimirimana <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Martin K. Petersen <[e-mail]>

drivers/scsi/pm8001/pm8001_defs.h

···
 #define	PM8001_MAX_PORTS	 16	/* max. possible ports */
 #define	PM8001_MAX_DEVICES	 2048	/* max supported device */
 #define	PM8001_MAX_MSIX_VEC	 64	/* max msi-x int for spcv/ve */
-#define	PM8001_RESERVE_SLOT	 8
+#define	PM8001_RESERVE_SLOT	 128
 
 #define PM8001_SECTOR_SIZE	512
 #define PM8001_PAGE_SIZE_4K	4096