LoongArch: Eliminate superfluous get_numa_distances_cnt()

In LoongArch, get_numa_distances_cnt() isn't in use, resulting in a
compiler warning.

Fix follow errors with clang-18 when W=1e:

arch/loongarch/kernel/acpi.c:259:28: error: unused function 'get_numa_distances_cnt' [-Werror,-Wunused-function]
  259 | static inline unsigned int get_numa_distances_cnt(struct acpi_table_slit *slit)
      |                            ^~~~~~~~~~~~~~~~~~~~~~
1 error generated.

Link: https://lore.kernel.org/all/Z7bHPVUH4lAezk0E@kernel.org/
Signed-off-by: Yuli Wang <wangyuli@uniontech.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

Author: Yuli Wang

arch/loongarch/kernel/acpi.c

@@ -249,18 +249,6 @@ static __init int setup_node(int pxm)
 	return acpi_map_pxm_to_node(pxm);
 }
 
-/*
- * Callback for SLIT parsing.  pxm_to_node() returns NUMA_NO_NODE for
- * I/O localities since SRAT does not list them.  I/O localities are
- * not supported at this point.
- */
-unsigned int numa_distance_cnt;
-
-static inline unsigned int get_numa_distances_cnt(struct acpi_table_slit *slit)
-{
-	return slit->locality_count;
-}
-
 void __init numa_set_distance(int from, int to, int distance)
 {
 	if ((u8)distance != distance || (from == to && distance != LOCAL_DISTANCE)) {