update the BLK_DEV_HD help text
update the BLK_DEV_HD help text

Many people will see this option the first time now that it is in
drivers/block/

Make it clear that virtually noone needs it.

Signed-off-by: Adrian Bunk <0b86548ef377da0031a3ff3f0c4e06f016e20105@kernel.org>
Cc: c2093e01fa868776d7876ac617ce6d2ac30cb904@arm.linux.org.uk
Cc: Alan Cox <91e38e63b890fbb214c8914809fde03c73e7f24d@lxorguk.ukuu.org.uk>
Signed-off-by: Bartlomiej Zolnierkiewicz <248de9df611a028e5eceb9d893a2ed6c24c89ef4@gmail.com>

TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs