doc: fix missing link target in Linux guide
doc: fix missing link target in Linux guide

Fix missing link in the Linux GSG, accidentally removed
in previous merge:

WARNING: undefined label: linux_gsg_compiling_dpdk

Fixes: 29c673401c4d ("doc: improve Linux guide layout")

Signed-off-by: John McNamara <af31595c36a4239b9676e9b3a777d3e2f15a6c4d@intel.com>
Acked-by: Bernard Iremonger <233eeff376ad0c06f66f06c5522ea3c4feb30d3b@intel.com>

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