iwlegacy: avoid warning about missing braces

iwlegacy: avoid warning about missing braces

commit 2cce76c3fab410520610a7d2f52faebc3cfcf843 upstream.

gcc-6 warns about code in il3945_hw_txq_ctx_free() being
somewhat ambiguous:

drivers/net/wireless/intel/iwlegacy/3945.c:1022:5: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses]

This adds a set of curly braces to avoid the warning.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>