Revert "arch: cxd56xx: Fix cxd56_usbdev.c for SMP"

Summary:
- The original commit was added to avoid hardfault but the
  root cause was the stack corruption which has been fixed by
  the previous commit. So let me revert the original commit.

Impact:
- SMP only

Testing:
- spresense:rndis_smp with nxplayer + telnet

This reverts commit 197187d826.

Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>

arch/arm/src/cxd56xx/cxd56_usbdev.c

@@ -1540,10 +1540,6 @@ static int cxd56_epinterrupt(int irq, FAR void *context)
   uint16_t len;
   int n;
 
-#ifdef CONFIG_SMP
-  irqstate_t flags = enter_critical_section();
-#endif
-
   eps = getreg32(CXD56_USB_DEV_EP_INTR);
     {
       for (n = 0; n < CXD56_NENDPOINTS; n++)
@@ -1817,10 +1813,6 @@ static int cxd56_epinterrupt(int irq, FAR void *context)
         }
     }
 
-#ifdef CONFIG_SMP
-  leave_critical_section(flags);
-#endif
-
   return OK;
 }
 
@@ -2593,10 +2585,6 @@ static int cxd56_epstall(FAR struct usbdev_ep_s *ep, bool resume)
   uint32_t ctrl;
   uint32_t addr;
 
-#ifdef CONFIG_SMP
-  irqstate_t flags = enter_critical_section();
-#endif
-
   addr = USB_ISEPIN(ep->eplog) ? CXD56_USB_IN_EP_CONTROL(privep->epphy)
                                : CXD56_USB_OUT_EP_CONTROL(privep->epphy);
 
@@ -2615,10 +2603,6 @@ static int cxd56_epstall(FAR struct usbdev_ep_s *ep, bool resume)
       privep->stalled = 1;
     }
 
-#ifdef CONFIG_SMP
-  leave_critical_section(flags);
-#endif
-
   return OK;
 }