irqchip/stm32: Add usart instances exti direct event support

Add following usart instances exti direct event support (used for UART wake
up).
- exti 26 (USART1) is mapped to GIC 37
- exti 27 (USART2) is mapped to GIC 38
- exti 28 (USART3) is mapped to GIC 39
- exti 29 (USART6) is mapped to GIC 71
- exti 31 (UART5) is mapped to GIC 53
- exti 32 (UART7) is mapped to GIC 82
- exti 33 (UART8) is mapped to GIC 83

Signed-off-by: Erwan Le Ray <[e-mail]>
Signed-off-by: Marc Zyngier <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/irqchip/irq-stm32-exti.c

···
 	{ .exti = 23, .irq_parent = 72, .chip = &stm32_exti_h_chip_direct },
 	{ .exti = 24, .irq_parent = 95, .chip = &stm32_exti_h_chip_direct },
 	{ .exti = 25, .irq_parent = 107, .chip = &stm32_exti_h_chip_direct },
+	{ .exti = 26, .irq_parent = 37, .chip = &stm32_exti_h_chip_direct },
+	{ .exti = 27, .irq_parent = 38, .chip = &stm32_exti_h_chip_direct },
+	{ .exti = 28, .irq_parent = 39, .chip = &stm32_exti_h_chip_direct },
+	{ .exti = 29, .irq_parent = 71, .chip = &stm32_exti_h_chip_direct },
 	{ .exti = 30, .irq_parent = 52, .chip = &stm32_exti_h_chip_direct },
+	{ .exti = 31, .irq_parent = 53, .chip = &stm32_exti_h_chip_direct },
+	{ .exti = 32, .irq_parent = 82, .chip = &stm32_exti_h_chip_direct },
+	{ .exti = 33, .irq_parent = 83, .chip = &stm32_exti_h_chip_direct },
 	{ .exti = 47, .irq_parent = 93, .chip = &stm32_exti_h_chip_direct },
 	{ .exti = 48, .irq_parent = 138, .chip = &stm32_exti_h_chip_direct },
 	{ .exti = 50, .irq_parent = 139, .chip = &stm32_exti_h_chip_direct },