tests: fp_sharing: Extract x86 configs to separate .conf

The SSE and SSE_FP_MATH configs exist only in the x86 architecture, so
extract them to a separate prj_x86.conf file for the fp_sharing test.

Fixes Kconfig warnings when building the test for frdm_k64f:
- warning: attempt to assign the value "y" to the undefined symbol SSE
- warning: attempt to assign the value "y" to the undefined symbol
  SSE_FP_MATH

Signed-off-by: Maureen Helm <maureen.helm@nxp.com>

tests/kernel/fp_sharing/prj.conf

@@ -1,6 +1,4 @@
 CONFIG_TEST=y
 CONFIG_FLOAT=y
-CONFIG_SSE=y
 CONFIG_FP_SHARING=y
-CONFIG_SSE_FP_MATH=y
 CONFIG_STDOUT_CONSOLE=y

tests/kernel/fp_sharing/prj_x86.conf

@@ -0,0 +1,6 @@
+CONFIG_TEST=y
+CONFIG_FLOAT=y
+CONFIG_SSE=y
+CONFIG_FP_SHARING=y
+CONFIG_SSE_FP_MATH=y
+CONFIG_STDOUT_CONSOLE=y

tests/kernel/fp_sharing/testcase.yaml

@@ -6,6 +6,7 @@ tests:
     tags: core
     timeout: 600
   kernel.fp_sharing.x86:
+    extra_args: CONF_FILE=prj_x86.conf
     platform_whitelist: qemu_x86
     slow: true
     tags: core