layer.conf: Fix the syntax for SIGGEN_EXCLUDE_SAFE_RECIPE_DEPS
layer.conf: Fix the syntax for SIGGEN_EXCLUDE_SAFE_RECIPE_DEPS

Signed-off-by: Khem Raj <729d64b6f67515e258459a5f6d20ec88b2caf8df@gmail.com>

linux4sam/meta-atmel,linux4sam/meta-atmel,linux4sam/meta-atmel,linux4sam/meta-atmel,linux4sam/meta-atmel