irqchip: Add missing MODULE_DESCRIPTION() macros

On x86, make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/irqchip/irq-ts4800.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/irqchip/irq-meson-gpio.o

Add the missing invocation of the MODULE_DESCRIPTION() macro to all
files which have a MODULE_LICENSE().  This includes a 3rd file,
irq-mvebu-pic.c, which did not produce a warning with the x86
allmodconfig, but which may cause this warning with other kernel
configurations.

Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20240608-md-drivers-irqchip-v1-1-dd02c3229277@quicinc.com