Shorten zio_* thread names

Linux kernel thread names are expected to be short.  This change shortens
the zio thread names to 10 characters leaving a few chracters to append
the /<cpuid> to which the thread is bound.  For example: z_wr_iss/0.

module/zfs/spa.c

@@ -95,7 +95,7 @@ typedef struct zio_taskq_info {
 } zio_taskq_info_t;
 
 static const char *const zio_taskq_types[ZIO_TASKQ_TYPES] = {
-	"issue", "issue_high", "intr", "intr_high"
+	"iss", "iss_h", "int", "int_h"
 };
 
 /*