tcti-libtpms: fix big endian response size. #1737

Job	Run time
coverity-test	0s
scanbuild	9m 45s
build-test (ubuntu-18.04, gcc)	8m 8s
test-coverage	5m 6s
build-test (ubuntu-18.04, clang)	5m 2s
test-fuzz	3m 28s
build-test (ubuntu-20.04, gcc)	4m 54s
test-mbedtls (ubuntu-20.04)	3m 2s
build-test (ubuntu-20.04, clang)	4m 42s
test-no-crypto-build	1m 29s
build-test (fedora-32, gcc)	9m 26s
test-mbedtls (ubuntu-22.04-mbedtls-3.1)	4m 1s
test-tcti-config	25m 42s
build-test (fedora-32, clang)	5m 25s
build-test (opensuse-leap, gcc)	9m 17s
build-test (opensuse-leap, clang)	4m 58s
build-test (ubuntu-22.04, gcc)	8m 9s
build-test (ubuntu-22.04, clang)	9m 28s
build-test (alpine-3.15, gcc)	4m 14s
build-test (alpine-3.15, clang)	8m 8s
	2h 14m 24s

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