bootparam.7: Remove crufty "Hard disks" options

[Part of a general change to remove cruft from this page.]
Much of the detail on device-driver specifics in this page dates
from the 20th century. (The last major update to this page was in
man-pages-1.14!) It's hugely out of date now (many of these
devices disappeared from the kernel years ago.) Arguably, this
kind of detail should never have been placed in a man page to
begin with, since devices come and go. Remove such text, and
where appropriate and possible add pointers to files in the
kernel Documentation/ directory.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man7/bootparam.7

@@ -562,11 +562,6 @@ Using this
 option tells the driver to make sure that both interfaces are never
 used at the same time.
 .TP
-.B "The 'hd=dtc2278' option"
-This option tells the driver that you have a DTC-2278D IDE interface.
-The driver then tries to do DTC-specific operations to enable the
-second interface and to enable faster transfer modes.
-.TP
 .B "The 'hd=noprobe' option"
 Do not probe for this drive.
 For example,
@@ -610,56 +605,6 @@ hd=cyls,heads,sects
 .IP
 If there are two disks installed, the above is repeated with the
 geometry parameters of the second disk.
-.TP
-.B "XT Disk Driver Options ('xd=')"
-If you are unfortunate enough to be using one of these old 8-bit cards
-that move data at a whopping 125kB/s, then here is the scoop.
-If the card is not recognized,
-you will have to use a boot argument of the form:
-
-.in +4n
-.nf
-xd=type,irq,iobase,dma_chan
-.fi
-.in
-.IP
-The type value specifies the particular manufacturer of the card,
-overriding autodetection.
-For the types to use, consult the
-.I drivers/block/xd.c
-source file of the kernel you are using.
-The type is an index in the list
-.I xd_sigs
-and in the course of time
-.\" 1.1.50, 1.3.81, 1.3.99, 2.0.34, 2.1.67, 2.1.78, 2.1.127
-types have been added to or deleted from the middle of the list,
-changing all type numbers.
-Today (Linux 2.5.0) the types are
-0=generic; 1=DTC 5150cx; 2,3=DTC 5150x; 4,5=Western Digital;
-6,7,8=Seagate; 9=Omti; 10=XEBEC, and where here several types are
-given with the same designation, they are equivalent.
-
-The xd_setup() function does no checking on the values, and assumes
-that you entered all four values.
-Don't disappoint it.
-Here is an
-example usage for a WD1002 controller with the BIOS disabled/removed,
-using the 'default' XT controller parameters:
-
-.in +4n
-.nf
-xd=2,5,0x320,3
-.fi
-.in
-.TP
-.B "Syquest's EZ* removable disks"
-Syntax:
-
-.in +4n
-.nf
-.BI ez= iobase[,irq[,rep[,nybble]]]
-.fi
-.in
 .SS Ethernet devices
 Different drivers make use of different parameters, but they all at
 least share having an IRQ, an I/O port base value, and a name.