ARM: qcom: scm: Clarify boot interface

The secure world only knows about 32-bit wide physical addresses
for the boot API. Clarify the kernel interface by explicitly
stating a u32 instead of phys_addr_t which could be 32 or 64 bits
depending on LPAE or not.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Kumar Gala <galak@codeaurora.org>