Fix building "generic" TRMM kernel with CMake

The CMake "TARGET_CORE" variables stores the "generic" target name in all lowercase letters, but gets compared to an all uppercase string, which results in the wrong TRMM kernel being selected.
This commit converts the TARGET_CORE to all uppercase before comparing its value to make sure case mismatches are not an issue in the future anymore.

kernel/CMakeLists.txt

@@ -187,10 +187,11 @@ function (build_core TARGET_CORE KDIR TSUFFIX KERNEL_DEFINITIONS)
     endif ()
     # Makefile.L3
     set(USE_TRMM false)
-    if (ARM OR ARM64 OR (TARGET_CORE MATCHES LONGSOON3B) OR (TARGET_CORE MATCHES GENERIC) OR (TARGET_CORE MATCHES HASWELL) OR (TARGET_CORE MATCHES ZEN) OR (TARGET_CORE MATCHES SKYLAKEX) OR (TARGET_CORE MATCHES COOPERLAKE))
+    string(TOUPPER ${TARGET_CORE} UC_TARGET_CORE)
+    if (ARM OR ARM64 OR (UC_TARGET_CORE MATCHES LONGSOON3B) OR (UC_TARGET_CORE MATCHES GENERIC) OR (UC_TARGET_CORE MATCHES HASWELL) OR (UC_TARGET_CORE MATCHES ZEN) OR (UC_TARGET_CORE MATCHES SKYLAKEX) OR (UC_TARGET_CORE MATCHES COOPERLAKE))
       set(USE_TRMM true)
     endif ()
-    if (ZARCH OR (TARGET_CORE MATCHES POWER8) OR (TARGET_CORE MATCHES POWER9) OR (TARGET_CORE MATCHES POWER10))
+    if (ZARCH OR (UC_TARGET_CORE MATCHES POWER8) OR (UC_TARGET_CORE MATCHES POWER9) OR (UC_TARGET_CORE MATCHES POWER10))
       set(USE_TRMM true)
     endif ()