USB: usb_bam: Fix compilation error to support LPAE

Targets having large physical address extension support
enabled (CONFIG_ARM_LPAE) phys_addr_t become 64-bit type.
Hence change of_property_read_u32 parameter to read 32-bit
value from device tree file.

Change-Id: I4ad3e98f114806c63e56491c1eb8523a8ec8033f
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>