scsi: ufs: core: Remove unnecessary ret in ufshcd_populate_vreg()

The local variable 'ret' is always zero. Remove it and return 0 at the end
of the function.

Link: https://lore.kernel.org/r/20210310082741.647-1-zbestahu@gmail.com


Signed-off-by: Yue Hu <huyue2@yulong.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>