treewide: Remove GO_PKG_LDFLAGS for stripping binaries
The "-s -w" flags in GO_PKG_LDFLAGS tells the Go compiler to strip the
binaries it produces. Since the default Go package build process will
strip binaries when CONFIG_USE_STRIP or CONFIG_USE_SSTRIP are selected,
these flags are unnecessary.
When CONFIG_NO_STRIP is selected, these flags override the user's
intention of building unstripped packages.
This removes these flags for all relevant packages.
Signed-off-by: Jeffery To <jeffery.to@gmail.com>