irqchip/mips-gic: Use bitfield helpers

Use the FIELD_GET() helper, instead of open-coding the same operation.

Signed-off-by: Geert Uytterhoeven <[e-mail]>
Signed-off-by: Marc Zyngier <[e-mail]>
Link: https://lore.kernel.org/all/74f9d[e-mail]

drivers/irqchip/irq-mips-gic.c

···
 
 #define pr_fmt(fmt) "irq-mips-gic: " fmt
 
+#include <linux/bitfield.h>
 #include <linux/bitmap.h>
 #include <linux/clocksource.h>
 #include <linux/cpuhotplug.h>
···
 	mips_gic_base = ioremap(gic_base, gic_len);
 
 	gicconfig = read_gic_config();
-	gic_shared_intrs = gicconfig & GIC_CONFIG_NUMINTERRUPTS;
-	gic_shared_intrs >>= __ffs(GIC_CONFIG_NUMINTERRUPTS);
+	gic_shared_intrs = FIELD_GET(GIC_CONFIG_NUMINTERRUPTS, gicconfig);
 	gic_shared_intrs = (gic_shared_intrs + 1) * 8;
 
 	if (cpu_has_veic) {