soc: qcom: glink: Use GFP_ATOMIC in memory allocation

All the rx notification callbacks are invoked from atomic
context. Memory allocation using GFP_KERNEL flags might sleep.

As the memory allocated during rx callback is immediately freed
upon worker thread completion, GFP_ATOMIC flag can be used to
allocate the memory.

CRs-Fixed: 896463
Change-Id: I722000e594e82b1fc1e72eade3f95e881577baf3
Signed-off-by: Atish Kumar Patra <apatra@codeaurora.org>