man page: Update to mktape

Long overdue update to the mktape command man page.

Signed-off-by: Mark Harvey <markh794@gmail.com>
TapeAlert: Clear flag(s) when log page 0x2e is read

Fixes a bug introduced with commit: 7e5b1c5b1f746d93d73a641b4f10fc038586e541
This commit resulted in TapeAlert flags not being cleared once
log page 0x2e is read.

Signed-off-by: Mark Harvey <markh794@gmail.com>