FAPI: fix problems detected by scanner. #2235

Job	Run time
build-test (ubuntu-20.04, gcc)	4m 42s
coverity-test	0s
build-test (ubuntu-20.04, clang)	4m 12s
build-test (fedora-32, gcc)	4m 40s
scanbuild	6m 34s
build-test (fedora-32, clang)	4m 56s
build-test (opensuse-leap, gcc)	4m 26s
build-test (opensuse-leap, clang)	4m 36s
test-coverage	5m 12s
build-test (ubuntu-22.04, gcc)	4m 25s
build-test (ubuntu-22.04, clang)	4m 23s
test-fuzz	2m 29s
build-test (alpine-3.15, gcc)	3m 56s
build-test (alpine-3.15, clang)	4m 40s
test-no-crypto-build	1m 15s
test-mbedtls (ubuntu-20.04)	2m 46s
test-tcti-config	14m 9s
test-mbedtls (ubuntu-22.04-mbedtls-3.1)	2m 48s
	1h 20m 9s

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