minor mods for mimicking NS83820 functionality

dev/ide_ctrl.cc:
    generalize these #defs
dev/ide_ctrl.hh:
    put these in pcireg.h
dev/ns_gige.cc:
    do i need io_enable?  and assert will fail if i actually need to implement it, which may give clue as to wehtehr i need to implmeent the mem_enable and bm_enable stuff.
dev/ns_gige.hh:
    implement this in case it's needed
dev/pcireg.h:
    put these defs in pcireg instead

--HG--
extra : convert_revision : 5e3581b5da17410f943907139bd479f15d2231e8

dev/ide_ctrl.cc

@@ -342,12 +342,12 @@ IdeController::WriteConfig(int offset, int size, uint32_t data)
     // (like updating the PIO ranges)
     switch (offset) {
       case PCI_COMMAND:
-        if (config.data[offset] & IOSE)
+        if (config.data[offset] & PCI_CMD_IOSE)
             io_enabled = true;
         else
             io_enabled = false;
 
-        if (config.data[offset] & BME)
+        if (config.data[offset] & PCI_CMD_BME)
             bm_enabled = true;
         else
             bm_enabled = false;