[PATCH v2] nvme: fix interpretation of dmrsl

[Christoph Hellwig]

This doesn't even compile:

drivers/nvme/host/core.c: In function ‘nvme_config_discard’:
drivers/nvme/host/core.c:1638:2: error: ISO C90 forbids mixed
declarations and code [-Werror=declaration-after-statement]
 1638 |  int lts_shift = ilog2(size) - 9;
      |  ^~~