cxl: update names for interleave granularity conversion macros

cxl: update names for interleave granularity conversion macros

Change names for granularity macros to clearly indicate which
variable is encoded and which is the actual granularity.

granularity == interleave granularity
eig == encoded interleave granularity

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alison Schofield <alison.schofield@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/167027493237.3124429.8948852388671827664.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>