buildroot config: add files to BR2_STRIP_EXCLUDE_FILES to avoid strip
In order to close source for the starfive libcamera ipa library,
consider the libcamera will sign the ipa library when install stage,
but generate the filesystem will strip all library by default, so need
to avoid strip for libcamera library
add below to BR2_STRIP_EXCLUDE_FILES to avoid strip
ipa_starfive.so*
libcamera-base.so*
libcamera.so*
libgstlibcamera.so
v4l2-compat.so
starfive_ipa_proxy
Signed-off-by: Andy Hu <andy.hu@starfivetech.com>