Kconfig: Fix backend options missing prefixes

TFM_SPM_BACKEND_[IPC/SFN] misses the "CONFIG_" prefix.
The tfm_kconfig.py removes the "CONFIG_" prefix in the generated
project_config.cmake.
While the TFM_SPM_BACKEND_[IPC/SFN] have the prefix in the CMake System.
So the option names in Kconfig need to prefixed.

This patch fixes the missing ones.

This issue does not bring bugs because the
tfm_[ipc/sfn]_config_default.cmake will set the value for
CONFIG_TFM_BACKEND_[IPC/SFN] anyway.

Change-Id: If0207ac0b1d005c38d94173e9237dee867d82b5e
Signed-off-by: Kevin Peng <kevin.peng@arm.com>
3 files changed