usb-ehci: Remove dead nakcnt code

This patch removes 2 bits of dead nakcnt code:

1) usb_ehci_execute calls ehci_qh_do_overlay which does:
nakcnt = reload;
and then has a block of code which is conditional on:
if (reload && !nakcnt) {
which ofcourse is never true now as nakcnt == reload.

2) ehci_state_fetchqh does:
nakcnt = reload;
but before nakcnt is ever used ehci_state_fetchqh is always followed
by a ehci_qh_do_overlay call which also does:
nakcnt = reload;
So doing this from ehci_state_fetchqh is redundant.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

hw/usb-ehci.c

@@ -1615,7 +1615,6 @@ static EHCIQueue *ehci_state_fetchqh(EHCIState *ehci, int async)
 {
     uint32_t entry;
     EHCIQueue *q;
-    int reload;
 
     entry = ehci_get_fetch_addr(ehci, async);
     q = ehci_find_queue_by_qh(ehci, entry, async);
@@ -1673,11 +1672,6 @@ static EHCIQueue *ehci_state_fetchqh(EHCIState *ehci, int async)
     }
 #endif
 
-    reload = get_field(q->qh.epchar, QH_EPCHAR_RL);
-    if (reload) {
-        set_field(&q->qh.altnext_qtd, reload, QH_ALTNEXT_NAKCNT);
-    }
-
     if (q->qh.token & QTD_TOKEN_HALT) {
         ehci_set_state(ehci, async, EST_HORIZONTALQH);
 
@@ -1837,25 +1831,11 @@ static void ehci_flush_qh(EHCIQueue *q)
 static int ehci_state_execute(EHCIQueue *q, int async)
 {
     int again = 0;
-    int reload, nakcnt;
-    int smask;
 
     if (ehci_qh_do_overlay(q) != 0) {
         return -1;
     }
 
-    smask = get_field(q->qh.epcap, QH_EPCAP_SMASK);
-
-    if (!smask) {
-        reload = get_field(q->qh.epchar, QH_EPCHAR_RL);
-        nakcnt = get_field(q->qh.altnext_qtd, QH_ALTNEXT_NAKCNT);
-        if (reload && !nakcnt) {
-            ehci_set_state(q->ehci, async, EST_HORIZONTALQH);
-            again = 1;
-            goto out;
-        }
-    }
-
     // TODO verify enough time remains in the uframe as in 4.4.1.1
     // TODO write back ptr to async list when done or out of time
     // TODO Windows does not seem to ever set the MULT field