net: increase default NAPI_SKB_CACHE_BULK to 32

net: increase default NAPI_SKB_CACHE_BULK to 32

The previous value 16 is a bit conservative, so adjust it along with
NAPI_SKB_CACHE_SIZE, which can minimize triggering memory allocation
in napi_skb_cache_get*().

Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jason Xing <kernelxing@tencent.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Link: https://patch.msgid.link/20251118070646.61344-3-kerneljasonxing@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>