ide-floppy: remove struct idefloppy_capabilities_page

This change is rather temporary and is in preparation of using generic commands
as is the case with ide-cd and the uniform cdrom layer (i.e. init_cdrom_command())
However, before this happens, we'll have to remove all typedefs and teach
idefloppy_create_mode_sense_cmd() to work directly on u8 buffers.

Also, since idefloppy_get_capability_page() was used to read only the sfrp bit,
rename the latter so that the name reflects what it does.

Signed-off-by: Borislav Petkov <bbpetkov@yahoo.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>