bcache: remove unnecessary select MIN_HEAP

After reverting the transition to the generic min heap library, bcache no
longer depends on MIN_HEAP. The select entry can be removed to reduce
code size and shrink the kernel's attack surface.

This change effectively reverts the bcache-related part of commit
92a8b224b833 ("lib/min_heap: introduce non-inline versions of min heap API
functions").

This is part of a series of changes to address a performance regression
caused by the use of the generic min_heap implementation.

As reported by Robert, bcache now suffers from latency spikes, with P100
(max) latency increasing from 600 ms to 2.4 seconds every 5 minutes.
These regressions degrade bcache's effectiveness as a low-latency cache
layer and lead to frequent timeouts and application stalls in production
environments.

Link: https://lore.kernel.org/lkml/[e-mail]
Link: https://lkml.kernel.org/r/[e-mail]
Fixes: 866898efbb25 ("bcache: remove heap-related macros and switch to generic min_heap")
Fixes: 92a8b224b833 ("lib/min_heap: introduce non-inline versions of min heap API functions")
Signed-off-by: Kuan-Wei Chiu <[e-mail]>
Reported-by: Robert Pang <[e-mail]>
Closes: https://lore.kernel.org/linux-bcache/[e-mail]
Acked-by: Coly Li <[e-mail]>
Cc: Ching-Chun (Jim) Huang <[e-mail]>
Cc: Kent Overstreet <[e-mail]>
Cc: <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

drivers/md/bcache/Kconfig

···
 	select BLOCK_HOLDER_DEPRECATED if SYSFS
 	select CRC64
 	select CLOSURES
-	select MIN_HEAP
 	help
 	Allows a block device to be used as cache for other devices; uses
 	a btree for indexing and the layout is optimized for SSDs.