irqchip/mchp-eic: Fix error code in mchp_eic_domain_alloc()

In the Linux kernel, the following vulnerability has been resolved: irqchip/mchp-eic: Fix error code in mchp_eic_domain_alloc() If irq_domain_translate_twocell() sets "hwirq" to >= MCHP_EIC_NIRQ (2) then it results in an out of bounds access. The code checks for invalid values, but doesn't set the error code. Return -EINVAL in that case, instead of returning success.