drivers: qcom: Add Bootloader timestamps to the boot_marker list

Bootloader captures the various timestamps like bootloader_start,
bootloader_end, kernel_load_start, and so on. Capture these timestamps
as part of the boot_marker list to know the Bootloader KPI values.

Change-Id: Ieaefa12074fff86b1af5f52c4083ab4bd00eaa6c
Signed-off-by: Shreyas K K <shrekk@codeaurora.org>