soc: qcom: smp2p: fix all kernel-doc warnings

soc: qcom: smp2p: fix all kernel-doc warnings

Use the documented notation for nested struct members.
Add a Return: comment for qcom_smp2p_intr().

These changes prevent these kernel-doc warnings:

smp2p.c:78: warning: Excess struct member 'name' description in 'smp2p_smem_item'
smp2p.c:78: warning: Excess struct member 'value' description in 'smp2p_smem_item'
smp2p.c:280: warning: No description found for return value of 'qcom_smp2p_intr'

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Bjorn Andersson <andersson@kernel.org>
Cc: Konrad Dybcio <konrad.dybcio@linaro.org>
Cc: linux-arm-msm@vger.kernel.org
Cc: Jeff Johnson <quic_jjohnson@quicinc.com>
Link: https://lore.kernel.org/r/20240123053329.12893-1-rdunlap@infradead.org
Signed-off-by: Bjorn Andersson <andersson@kernel.org>