config: fix kni build

config: fix kni build

When building kernel modules such as kni, the "config" directory is not
passed as a standard path in the EXTRA_CFLAGS value, meaning that the
rte_compatibility_defines.h is not found from rte_config.h. However, since
both headers are in the same directory, we can just use quotes rather than
angle-brackets to ensure the second header is always found if the first is.

Fixes: b0b672aeadaa ("build: add defines for compatibility with make build")

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: David Marchand <david.marchand@redhat.com>