soc: qcom: boot_marker: change module load order

boot_marker's routine place_marker used by module's
which start late in driver initialization at kernel boot
sequence hence required chaning its load order.
boot_marker module depends on boot_stat which load order
is subsys_initcall hence changing boot_marker as subsys
module.

CRs-Fixed: 1023644
Change-Id: I6c44d59d1899667f92d25211a2af4edde7130e15
Signed-off-by: Atul Raut <araut@codeaurora.org>