cnss2: Correctly check for WCNSS_MEM_PRE_ALLOC macro
After CNSS2 switched to Bazel based compilation, conditional
compilation macros became same as configs and are enabled
directly from defconfig. Fix macro check in the code for
both y or m to enable code based on the that.
Change-Id: Icd65573b02d95198e26c37ebe4ac93839cf21ad9
CRs-Fixed: 3553530