net: lwm2m: Reduce dependency on firmware update pull Kconfig

There are functions whose headers are only visible when
CONFIG_LWM2M_FIRMWARE_UPDATE_PULL_SUPPORT is selected. However these
functions are used outside the scope of the firmware update pull
functionality. This change allows to disable
CONFIG_LWM2M_FIRMWARE_UPDATE_PULL_SUPPORT while still being able to use
the firmware update object.

Signed-off-by: Marc Lasch <[email protected]>

Author: mlasch

include/zephyr/net/lwm2m.h

@@ -551,7 +551,6 @@ void lwm2m_firmware_set_cancel_cb_inst(uint16_t obj_inst_id, lwm2m_engine_user_c
  */
 lwm2m_engine_user_cb_t lwm2m_firmware_get_cancel_cb_inst(uint16_t obj_inst_id);
 
-#if defined(CONFIG_LWM2M_FIRMWARE_UPDATE_PULL_SUPPORT) || defined(__DOXYGEN__)
 /**
  * @brief Set data callback to handle firmware update execute events.
  *
@@ -588,8 +587,6 @@ void lwm2m_firmware_set_update_cb_inst(uint16_t obj_inst_id, lwm2m_engine_execut
  */
 lwm2m_engine_execute_cb_t lwm2m_firmware_get_update_cb_inst(uint16_t obj_inst_id);
 #endif
-#endif
-
 
 #if defined(CONFIG_LWM2M_SWMGMT_OBJ_SUPPORT) || defined(__DOXYGEN__)