memdisk: Fix order of sectors/track and bytes/sector

memdisk: Fix order of sectors/track and bytes/sector

Swap order of sectors/track with bytes/sector to match diskette
parameter table order (as pointed to by INT 1Eh).

References: (additional ones available if necessary)
'System BIOS for IBM PC/XT/AT computers and compatibles' by Phoenix
Technologies Ltd. copyright 1987,88,89 3rd printing 1990 ISBN:
0-201-51806-6 pages 61-62
'PC Interrupts' 2nd edition by Ralf Brown & Jim Kyle copyright 1994
1st printing 1993 ISBN: 0-201-62485-0 page 211

Note: this fixes an issue with older FreeDOS kernels that expect this
structure to contain valid values.

Signed-off-by: Kenneth J. Davis <jeremyd@fdos.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>