hlr.c: move hlr_ctx to the top

Allow all functions to use hlr_ctx, so it can be used by the upcoming
read_cb_forward() function in [1]. That new function is placed next to
the existing read_cb() function, which is above the current hlr_ctx
declaration.

[1]: Change-Id: Ia4f345abc877baaf0a8f73b8988e6514d9589bf5

Related: OS#3793
Change-Id: I5edf0a233ff323a63e321a1ca47736b5b212d1bb
1 file changed