libssl: unbreak building the library with KTLS

The 3.5.1 update dropped a `SRCS` entry for the MK_OPENSSL_KTLS != no
case (the source was renamed from `ktls.c` to `ktls_meth.c`). Add the
new file to SRCS in order to unbreak linking the library when KTLS is
enabled.

This bug isn't apparent now because KTLS is always disabled in
`include/openssl/configuration.h` (this will be fixed soon).

Found when doing `make universe` with KTLS enabled in
`include/openssl/configuration.h`.

Fixes:	4757b35 ("openssl: Import version 3.5.1")

Author: ngie-eign

secure/lib/libssl/Makefile

@@ -73,6 +73,8 @@ SRCS+=	rio_notifier.c poll_builder.c
 
 .if ${MK_OPENSSL_KTLS} == "no"
 CFLAGS+=-DOPENSSL_NO_KTLS
+.else
+SRCS+=	ktls_meth.c
 .endif
 
 LIBADD=	crypto