[CentOS] Adjust type of rw in submit_bio from int to unsigned long

Hi, I am a developer who worked on CentOS. Recently I am working on porting one of my
block drivers from CentOS 6.x to CentOS 7.x. In newest kernel (kernel-3.10.0-693.17.1.el7)
I found there is an issue in submit_bio()'s first argument:
    void submit_bio(int rw, struct bio *bio)
The type of bi_rw of struct bio is unsigned long, and the number of enum rq_flags_bits
also exceeds 32, so we should better using unsigned long for rw in submit_bio(), like:
    void submit_bio(unsigned long rw, struct bio *bio)