template_kem.c: Use proper printf format for size_t #1136

Job	Run time
run-checker (enable-asan enable-ubsan no-shared no-asm -DOPENSSL_SMALL_FOOTPRINT -fno-sanitize=fu...	9m 59s
jitter	6m 12s
run-checker (no-dso)	5m 21s
run-checker (no-dynamic-engine)	5m 17s
run-checker (no-ec2m enable-fips)	5m 55s
run-checker (no-engine no-shared)	4m 23s
run-checker (no-err)	5m 35s
run-checker (no-filenames)	5m 35s
run-checker (enable-ubsan no-asm -DOPENSSL_SMALL_FOOTPRINT -fno-sanitize=function)	8m 37s
run-checker (no-module)	5m 34s
run-checker (no-ocsp)	5m 36s
run-checker (no-pinshared)	5m 35s
run-checker (no-srp)	5m 38s
run-checker (no-srtp)	5m 39s
run-checker (no-ts)	5m 36s
run-checker (no-integrity-only-ciphers)	5m 36s
run-checker (enable-weak-ssl-ciphers)	5m 38s
run-checker (enable-zlib)	5m 34s
run-checker (enable-pie)	5m 38s
	1h 52m 58s

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