[MIPS] Alchemy: fix IRQ bases

Do what the commits commits f3e8d1da389fe2e514e31f6e93c690c8e1243849 and
9d360ab4a7568a8d177280f651a8a772ae52b9b9 failed to achieve -- actually
convert the Alchemy code to irq_cpu.

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2 files changed