fix error: label at end of compound statement

[umeiko]

My envirment: Ubuntu 20.04, gcc-arm-none-eabi: 15:9-2019-q4-0ubuntu1
When I tried to compile lk2nd with make TOOLCHAIN_PREFIX=arm-none-eabi- lk2nd-msm8952, meet error :

  lk2nd/boot/extlinux.c: In function 'parse_conf':
  lk2nd/boot/extlinux.c:224:4: error: label at end of compound statement
    224 |    default:
        |    ^~~~~~~
  make[1]: *** [arch/arm/compile.mk:5: build-lk2nd-msm8952/lk2nd/boot/extlinux.o] Error 1

I fixed this by added break after default case.

[Danct12]

CC: @TravMurav

[TravMurav]

Queued that as a fixup, will be squashed in later. Thanks!

msm8916-mainline@aaa9efa