net: qualcomm: rmnet: Remove the some redundant macros

Multiplexing is always enabled when transmiting from a rmnet device,
so remove the redundant egress macros. De-multiplexing is always
enabled when receiving packets from a rmnet device, so remove those
ingress macros.

CRs-Fixed: 2156182
Change-Id: I128dac3cb839dcb624907b1fcfd36ed3e268f977
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>