irqchip/bmips: Replace cpumask_weight() with cpumask_empty()

irqchip/bmips: Replace cpumask_weight() with cpumask_empty()

bcm6345_l1_of_init() calls cpumask_weight() to check if any bit of a given
cpumask is set.

This can be done more efficiently with cpumask_empty() because
cpumask_empty() stops traversing the cpumask as soon as it finds first set
bit, while cpumask_weight() counts all bits unconditionally.

Signed-off-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20220210224933.379149-21-yury.norov@gmail.com