b43: main: Add braces around empty statements

Fixes the following W=1 kernel build warning(s):

 drivers/net/wireless/broadcom/b43/main.c: In function ‘b43_dummy_transmission’:
 drivers/net/wireless/broadcom/b43/main.c:785:3: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
 drivers/net/wireless/broadcom/b43/main.c: In function ‘b43_do_interrupt_thread’:
 drivers/net/wireless/broadcom/b43/main.c:2017:3: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]

Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Martin Langer <martin-langer@gmx.de>
Cc: Stefano Brivio <stefano.brivio@polimi.it>
Cc: Michael Buesch <m@bues.ch>
Cc: van Dyk <kugelfang@gentoo.org>
Cc: Andreas Jaggi <andreas.jaggi@waterwave.ch>
Cc: Albert Herranz <albert_herranz@yahoo.es>
Cc: linux-wireless@vger.kernel.org
Cc: b43-dev@lists.infradead.org
Cc: netdev@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200814113933.1903438-8-lee.jones@linaro.org

drivers/net/wireless/broadcom/b43/main.c

@@ -781,8 +781,9 @@ void b43_dummy_transmission(struct b43_wldev *dev, bool ofdm, bool pa_on)
 	b43_write16(dev, B43_MMIO_XMTSEL, 0x0826);
 	b43_write16(dev, B43_MMIO_TXE0_CTL, 0x0000);
 
-	if (!pa_on && phy->type == B43_PHYTYPE_N)
+	if (!pa_on && phy->type == B43_PHYTYPE_N) {
 		; /*b43_nphy_pa_override(dev, false) */
+	}
 
 	switch (phy->type) {
 	case B43_PHYTYPE_N:
@@ -2013,8 +2014,9 @@ static void b43_do_interrupt_thread(struct b43_wldev *dev)
 		handle_irq_beacon(dev);
 	if (reason & B43_IRQ_PMQ)
 		handle_irq_pmq(dev);
-	if (reason & B43_IRQ_TXFIFO_FLUSH_OK)
+	if (reason & B43_IRQ_TXFIFO_FLUSH_OK) {
 		;/* TODO */
+	}
 	if (reason & B43_IRQ_NOISESAMPLE_OK)
 		handle_irq_noise(dev);