unix: add more block device ioctl numbers

This adds a few additional ioctl numbers for performing various block
device operations.

Change-Id: I1dc836f4017bbc175b2dee759fece728f1caa010
Reviewed-on: https://go-review.googlesource.com/c/sys/+/511597
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
Run-TryBot: Bryan Mills <bcmills@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

Author: lorenz

unix/mkerrors.sh

@@ -624,7 +624,7 @@ ccflags="$@"
 		$2 ~ /^MEM/ ||
 		$2 ~ /^WG/ ||
 		$2 ~ /^FIB_RULE_/ ||
-		$2 ~ /^BLK[A-Z]*(GET$|SET$|BUF$|PART$|SIZE)/ {printf("\t%s = C.%s\n", $2, $2)}
+		$2 ~ /^BLK[A-Z]*(GET$|SET$|BUF$|PART$|SIZE|IOMIN$|IOOPT$|ALIGNOFF$|DISCARD|ROTATIONAL$|ZEROOUT$|GETDISKSEQ$)/ {printf("\t%s = C.%s\n", $2, $2)}
 		$2 ~ /^__WCOREFLAG$/ {next}
 		$2 ~ /^__W[A-Z0-9]+$/ {printf("\t%s = C.%s\n", substr($2,3), $2)}