It's not necessary to release resource which allocated with devm_*
and those release may leads to a double free. And also remove useless
irq_dispose_mapping() call since mapping not created.

Fixes: 09aab7ad ("i2c: mpc: use device managed APIs")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Signed-off-by: Wolfram Sang <wsa@kernel.org>