net: remove duplicate INDIRECT_CALLABLE_DECLARE of udp[6]_ehashfn

net: remove duplicate INDIRECT_CALLABLE_DECLARE of udp[6]_ehashfn

There are already INDIRECT_CALLABLE_DECLARE in the hashtable
headers, no need to declare them again.

Fixes: 0f495f761722 ("net: remove duplicate reuseport_lookup functions")
Suggested-by: Martin Lau <martin.lau@linux.dev>
Signed-off-by: Lorenz Bauer <lmb@isovalent.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20230731-indir-call-v1-1-4cd0aeaee64f@isovalent.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>