fix(ufs): don't zero out buf before ufs read

ufs_read_blocks always zeros out the buffer before passing
to UFS for DMA. We don't need to zero out buf before reading
from UFS storage, this change remove the memset in ufs_read_blocks.

Signed-off-by: Channa Kadabi <kadabi@google.com>
Change-Id: I8029a7ea07fbd8cce29b383c80a3cfc782c5b7ec

drivers/ufs/ufs.c

@@ -702,7 +702,6 @@ size_t ufs_read_blocks(int lun, int lba, uintptr_t buf, size_t size)
 	       (ufs_params.desc_base != 0) &&
 	       (ufs_params.desc_size >= UFS_DESC_SIZE));
 
-	memset((void *)buf, 0, size);
 	get_utrd(&utrd);
 	ufs_prepare_cmd(&utrd, CDBCMD_READ_10, lun, lba, buf, size);
 	ufs_send_request(utrd.task_tag);