[SCSI] bfa: remove os wrapper and unused functions

This patch removes os wrapper and unused functions.
bfa_os_assign(), bfa_os_memset(), bfa_os_memcpy(), bfa_os_udelay()
bfa_os_vsprintf(), bfa_os_snprintf(), and bfa_os_get_clock() are replaced with
direct assignment or native linux functions. Some unused functions related to VF
(Vitual fabric) are also removed.

Signed-off-by: Jing Huang <huangj@brocade.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>