bnxt_en: The caller of bnxt_alloc_ctx_mem() should always free bp->ctx

bnxt_en: The caller of bnxt_alloc_ctx_mem() should always free bp->ctx

bnxt_alloc_ctx_mem() calls bnxt_hwrm_func_backing_store_qcaps() to
allocate the memory for bp->ctx.  Initialize bp->ctx with the allocated
memory and let the caller free it during unwind.  The unwind logic is
already there, we just need to always set bp->ctx to the allocated
memory so the caller will always free it.  This simplifies the logic
and makes it easier to expand on the backing store logic.

Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Reviewed-by: Somnath Kotur <somnath.kotur@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Link: https://lore.kernel.org/r/20231120234405.194542-2-michael.chan@broadcom.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>