Remove unnecessary break statements

Fix these warnings from cppcheck:

hw/display/cirrus_vga.c:2603:
hw/sd/sd.c:348:
hw/timer/exynos4210_mct.c:1033:
target-arm/translate.c:9886:
target-s390x/mem_helper.c:518:
target-unicore32/translate.c:1936:
 style: Consecutive return, break, continue, goto or throw statements are unnecessary.
Signed-off-by: NStefan Weil <sw@weilnetz.de>
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: NAndreas Färber <afaerber@suse.de>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

hw/display/cirrus_vga.c

@@ -2600,7 +2600,6 @@ static void cirrus_vga_ioport_write(void *opaque, hwaddr addr, uint64_t val,
 #endif
 	cirrus_vga_write_sr(c, val);
         break;
-	break;
     case 0x3c6:
 	cirrus_write_hidden_dac(c, val);
 	break;

hw/timer/exynos4210_mct.c

@@ -1030,7 +1030,6 @@ static uint64_t exynos4210_mct_read(void *opaque, hwaddr offset,
     case G_INT_ENB:
         value = s->g_timer.reg.int_enb;
         break;
-        break;
     case G_WSTAT:
         value = s->g_timer.reg.wstat;
         break;

target-arm/translate.c

@@ -9916,7 +9916,6 @@ static inline void gen_intermediate_code_internal(CPUARMState *env,
                        invalidate this TB.  */
                     dc->pc += 2;
                     goto done_generating;
-                    break;
                 }
             }
         }

target-s390x/mem_helper.c

@@ -515,7 +515,6 @@ uint32_t HELPER(ex)(CPUS390XState *env, uint32_t cc, uint64_t v1,
             break;
         default:
             goto abort;
-            break;
         }
     } else if ((insn & 0xff00) == 0x0a00) {
         /* supervisor call */

target-unicore32/translate.c

@@ -1933,7 +1933,6 @@ static inline void gen_intermediate_code_internal(CPUUniCore32State *env,
                        invalidate this TB.  */
                     dc->pc += 2; /* FIXME */
                     goto done_generating;
-                    break;
                 }
             }
         }