msm: rpc_server_handset: Fix section mismatch

WARNING: vmlinux.o(.devinit.text+0x228): Section mismatch in
reference from the function hs_rpc_init() to the function
.init.text:hs_rpc_cb_init()
The function __devinit hs_rpc_init() references
a function __init hs_rpc_cb_init().
If hs_rpc_cb_init is only used by hs_rpc_init then
annotate hs_rpc_cb_init with a matching annotation.

Change-Id: I40b596f1b851801dc9b2a19c39429faf6435be39
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>