firmware: qcom: qseecom: convert to using the TZ allocator

Drop the DMA mapping operations from qcom_scm_qseecom_app_send() and
convert all users of it in the qseecom module to using the TZ allocator
for creating SCM call buffers. As this is largely a module separate from
the SCM driver, let's use a separate memory pool. Set the initial size to
4K and - if we run out - add twice the current amount to the pool.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Elliot Berman <quic_eberman@quicinc.com>
Reviewed-by: Amirreza Zarrabi <quic_azarrabi@quicinc.com>
Link: https://lore.kernel.org/r/20240527-shm-bridge-v10-9-ce7afaa58d3a@linaro.org
Signed-off-by: Bjorn Andersson <andersson@kernel.org>