powerpc/module: Remove unused .ftrace.tramp section

.ftrace.tramp section is not used for any purpose. This code was added
all the way back in the original commit introducing support for dynamic
ftrace on ppc64 modules. Remove it.

Signed-off-by: Naveen N Rao <naveen@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/9cf6d7f37ba82f7cb6dafecf660f44925c526d8d.1687166935.git.naveen@kernel.org