boards: arm64: intel_socfpga: Move boards to subdirectories

Adjust boards directory structure to SoC structure:

 `boards/intel/intel_socfpga_agilex_socdk` ->
     `boards/intel/intel_socfpga/agilex_socdk`
 `boards/intel/intel_socfpga_agilex5_socdk` ->
     `boards/intel/intel_socfpga/agilex5_socdk`

Signed-off-by: Dmitrii Golovanov <dmitrii.golovanov@intel.com>

boards/intel/intel_socfpga/agilex5_socdk/doc/index.rst

@@ -45,7 +45,7 @@ hardware features:
 NOTE: TODO, more details on dev kit will be updated as and when available.
 
 The default configuration can be found in the defconfig file:
-        `boards/intel/intel_socfpga_agilex5_socdk/intel_socfpga_agilex5_socdk_defconfig`
+        `boards/intel/intel_socfpga/agilex5_socdk/intel_socfpga_agilex5_socdk_defconfig`
 
 Programming and Debugging
 *************************

boards/intel/intel_socfpga/agilex_socdk/doc/index.rst

@@ -42,7 +42,7 @@ Other hardware features have not been enabled yet for this board.
 
 The default configuration can be found in the defconfig file:
 
-        ``boards/intel/intel_socfpga_agilex_socdk/intel_socfpga_agilex_socdk_defconfig``
+        ``boards/intel/intel_socfpga/agilex_socdk/intel_socfpga_agilex_socdk_defconfig``
 
 Programming and Debugging
 *************************