NXP Backend: Fix Coverity problems in neutron backend #1912

Job	Run time
test-vulkan / test-backend-linux (vulkan, operators) / linux-job	20m 22s
test-vulkan / test-backend-linux (vulkan, models) / linux-job	20m 52s
test-vulkan / test-backend-macos	0s
test-vulkan / package-golden-artifacts	3m 34s
	44m 48s

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