doc: remove reference to rte.doc.mk in programmers guide
doc: remove reference to rte.doc.mk in programmers guide

This patch removes the reference to rte.doc.mk in
DPDK programmers guide.

Fixes: ee801f6cc7b8 ("mk: clean dead doc rules")
Cc: stable@dpdk.org

Signed-off-by: Rami Rosen <d906574dd7f018d5d95e7b7a8107cdf708745f05@gmail.com>
Reviewed-by: Ferruh Yigit <ba8734c3c506d2e3557bd4ac8fdaccd25bdb9aa7@intel.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk