test: ztest: use YAML lists for tags

Convert deprecated space-separated tag declarations to YAML lists so
Twister test discovery works with current Zephyr.

Signed-off-by: Tomasz Leman <tomasz.m.leman@intel.com>

Author: tmleman

test/ztest/unit/fast-get/testcase.yaml

@@ -7,7 +7,7 @@
 
 tests:
   sof.unit.fast_get:
-    tags: fast_get memory cache
+    tags: [fast_get, memory, cache]
     platform_allow: native_sim
     integration_platforms:
       - native_sim

test/ztest/unit/math/advanced/functions/testcase.yaml

@@ -10,7 +10,7 @@
 
 tests:
   sof.unit.math.advanced.functions:
-    tags: math advanced functions power logarithm base2 base10 exponential exp db2lin sqrt log10
+    tags: [math, advanced, functions, power, logarithm, base2, base10, exponential, exp, db2lin, sqrt, log10]
     platform_allow: native_sim
     integration_platforms:
       - native_sim

test/ztest/unit/math/basic/arithmetic/testcase.yaml

@@ -10,7 +10,7 @@
 
 tests:
   sof.unit.math.basic.arithmetic:
-    tags: math arithmetic numbers
+    tags: [math, arithmetic, numbers]
     platform_allow: native_sim
     integration_platforms:
       - native_sim