arm64: defconfig: Visconti: Enable PWM

Enable Visconti's PWM in the ARM64 defconfig as a module.
Signed-off-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>

arch/arm64/configs/defconfig

@@ -1083,6 +1083,7 @@ CONFIG_PWM_SAMSUNG=y
 CONFIG_PWM_SL28CPLD=m
 CONFIG_PWM_SUN4I=m
 CONFIG_PWM_TEGRA=m
+CONFIG_PWM_VISCONTI=m
 CONFIG_SL28CPLD_INTC=y
 CONFIG_QCOM_PDC=y
 CONFIG_RESET_IMX7=y