scsi: aacraid: Fix spelling of "its"

Use the possessive "its" instead of the contraction "it's" in user
messages.

Link: https://lore.kernel.org/r/[e-mail]
Cc: Adaptec OEM Raid Solutions <[e-mail]>
Cc: "James E.J. Bottomley" <[e-mail]>
Cc: "Martin K. Petersen" <[e-mail]>
Signed-off-by: Randy Dunlap <[e-mail]>
Signed-off-by: Martin K. Petersen <[e-mail]>

drivers/scsi/aacraid/aachba.c

···
 	" 0=PIC(default), 1=MSI, 2=MSI-X)");
 module_param(startup_timeout, int, S_IRUGO|S_IWUSR);
 MODULE_PARM_DESC(startup_timeout, "The duration of time in seconds to wait for"
-	" adapter to have it's kernel up and\n"
+	" adapter to have its kernel up and\n"
 	"running. This is typically adjusted for large systems that do not"
 	" have a BIOS.");
 module_param(aif_timeout, int, S_IRUGO|S_IWUSR);