bootloader: disable psram cache bug fix for bootloader
The psram cache bug fix was also being applied to the bootloader binary (for cmake),
which doesnt do any psram access.
Applying this fix would increase the binary size, as much as 300 bytes in worst case scenarios
-if(CONFIG_SPIRAM_CACHE_WORKAROUND)
+if(CONFIG_SPIRAM_CACHE_WORKAROUND AND NOT BOOTLOADER_BUILD)
# We do this here as well as in CMakeLists.txt, because targets that
# are not part of the ESP-IDF build system (for cases where a generic
# non-IDF CMakeLists.txt file is imported into a component) don't depend
