kasan, arm64: remove redundant ARCH_SLAB_MINALIGN define

Defining ARCH_SLAB_MINALIGN in arch/arm64/include/asm/cache.h when KASAN
is off is not needed, as it is defined in defined in include/linux/slab.h
as ifndef.
Signed-off-by: NAndrey Konovalov <andreyknvl@google.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

arch/arm64/include/asm/cache.h

@@ -60,8 +60,6 @@
 
 #ifdef CONFIG_KASAN_SW_TAGS
 #define ARCH_SLAB_MINALIGN	(1ULL << KASAN_SHADOW_SCALE_SHIFT)
-#else
-#define ARCH_SLAB_MINALIGN	__alignof__(unsigned long long)
 #endif
 
 #ifndef __ASSEMBLY__