SWAP-DA: remove invalid semicolons on energy module

SWAP-DA: remove invalid semicolons on energy module

There are invalid semicolons after if clause on energy module and
it causes following build error with gcc 6, so this patch removes
the invalid semicolons.

  kernel/swap/energy/energy.c: In function 'calc_wifi_recv_energy':
  kernel/swap/energy/energy.c:640:2: error: this 'if' clause does not guard... [-Werror=misleading-indentation]
    if (len <= 0 || check_wlan0(sock));
    ^~
  kernel/swap/energy/energy.c:641:3: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'if'
     return;
     ^~~~~~
  kernel/swap/energy/energy.c: In function 'calc_wifi_send_energy':
  kernel/swap/energy/energy.c:653:2: error: this 'if' clause does not guard... [-Werror=misleading-indentation]
    if (len <= 0 || check_wlan0(sock));
    ^~
  kernel/swap/energy/energy.c:654:3: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'if'
     return;
     ^~~~~~

Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>