hw/intc/riscv_aplic: Fix in_clrip[x] read emulation

hw/intc/riscv_aplic: Fix in_clrip[x] read emulation

The reads to in_clrip[x] registers return rectified input values of the
interrupt sources.

A rectified input value of an interrupt source is defined by the section
"4.5.2 Source configurations (sourcecfg[1]–sourcecfg[1023])" of the RISC-V
AIA specification as:
"rectified input value = (incoming wire value) XOR (source is inverted)"

Update the riscv_aplic_read_input_word() implementation to match the above.

Fixes: e8f79343cfc8 ("hw/intc: Add RISC-V AIA APLIC device emulation")
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Message-ID: <20240306095722.463296-3-apatel@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>