Revert "lib: Add CONFIG_LIB_KMEM_CACHE for full kmem_cache support"

The memory leaks were in fact not coming from the kmem cache, so let's
drop this unnecessary feature.

This reverts commit e63fc511c3.

Signed-off-by: Simon Glass <simon.glass@canonical.com>

lib/Kconfig

@@ -396,14 +396,6 @@ config TPL_TINY_MEMSET
 config RBTREE
 	bool
 
-config LIB_KMEM_CACHE
-	bool "Enable full kmem_cache implementation"
-	help
-	  Provide a proper kmem_cache implementation in lib/linux_compat.c
-	  that tracks allocated objects. This is needed by subsystems like
-	  ext4 that require cache management. When disabled, simple inline
-	  stubs are used instead.
-
 config BITREVERSE
 	bool "Bit reverse library from Linux"
 

lib/Makefile

@@ -136,7 +136,6 @@ obj-$(CONFIG_$(PHASE_)OF_LIBFDT) += fdtdec.o fdtdec_common.o fdt_print.o
 obj-y += hang.o
 obj-y += linux_compat.o
 obj-y += linux_string.o
-obj-$(CONFIG_$(PHASE_)LIB_KMEM_CACHE) += kmem_cache.o
 obj-$(CONFIG_$(PHASE_)LMB) += lmb.o
 obj-y += membuf.o
 obj-$(CONFIG_REGEX) += slre.o

lib/kmem_cache.c

@@ -1,20 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0+
-/*
- * kmem_cache implementation for U-Boot
- *
- * Copyright 2025 Canonical Ltd
- * Written by Simon Glass <simon.glass@canonical.com>
- */
-
-#include <malloc.h>
-#include <linux/slab.h>
-
-void kmem_cache_free(struct kmem_cache *cachep, void *obj)
-{
-	free(obj);
-}
-
-void kmem_cache_destroy(struct kmem_cache *cachep)
-{
-	free(cachep);
-}