examples/ntb: fix build dependency
examples/ntb: fix build dependency

Caught while building with -Ddisable_drivers=*/*.
This example requires raw/ntb specific API.
Fix dependency to avoid a compilation error:

FAILED: examples/c590b3c@@dpdk-ntb@exe/ntb_ntb_fwd.c.o
ccache gcc -Iexamples/c590b3c@@dpdk-ntb@exe -Iexamples -I../examples
  -Iexamples/ntb -I../examples/ntb -I. -I../ -Iconfig -I../config
  -Ilib/eal/include -I../lib/eal/include -Ilib/eal/linux/include
  -I../lib/eal/linux/include -Ilib/eal/x86/include
  -I../lib/eal/x86/include -Ilib/eal/common -I../lib/eal/common
  -Ilib/eal -I../lib/eal -Ilib/kvargs -I../lib/kvargs
  -Ilib/telemetry/../metrics -I../lib/telemetry/../metrics
  -Ilib/telemetry -I../lib/telemetry -Ilib/mempool -I../lib/mempool
  -Ilib/ring -I../lib/ring -Ilib/net -I../lib/net -Ilib/mbuf
  -I../lib/mbuf -Ilib/ethdev -I../lib/ethdev -Ilib/meter
  -I../lib/meter -Ilib/cmdline -I../lib/cmdline -Ilib/rawdev
  -I../lib/rawdev -fdiagnostics-color=always -pipe -Wall
  -Winvalid-pch -Werror -O2 -g -include rte_config.h -Wextra
  -Wcast-qual -Wdeprecated -Wformat -Wformat-nonliteral
  -Wformat-security -Wmissing-declarations -Wmissing-prototypes
  -Wnested-externs -Wold-style-definition -Wpointer-arith
  -Wsign-compare -Wstrict-prototypes -Wundef -Wwrite-strings
  -Wno-missing-field-initializers -D_GNU_SOURCE -march=corei7
  -Wno-format-truncation -D_FILE_OFFSET_BITS=64
  -DALLOW_EXPERIMENTAL_API  -MD
  -MQ 'examples/c590b3c@@dpdk-ntb@exe/ntb_ntb_fwd.c.o'
  -MF 'examples/c590b3c@@dpdk-ntb@exe/ntb_ntb_fwd.c.o.d'
  -o 'examples/c590b3c@@dpdk-ntb@exe/ntb_ntb_fwd.c.o'
  -c ../examples/ntb/ntb_fwd.c
../examples/ntb/ntb_fwd.c:21:10: fatal error: rte_pmd_ntb.h:
  No such file or directory
 #include <rte_pmd_ntb.h>
          ^~~~~~~~~~~~~~~
compilation terminated.

Fixes: 5194299d6ef5 ("examples/ntb: support more functions")
Cc: stable@dpdk.org

Signed-off-by: David Marchand <f28529695cfa9e3e1eb84e7072aa626af4abb18e@redhat.com>

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