Merge changes from topic "pie" into integration
* changes:
uniphier: make all BL images completely position-independent
uniphier: make uniphier_mmap_setup() work with PIE
uniphier: pass SCP base address as a function parameter
uniphier: set buffer offset and length for io_block dynamically
uniphier: use more mmap_add_dynamic_region() for loading images
bl_common: add BL_END macro
uniphier: turn on ENABLE_PIE
TSP: add PIE support
BL2_AT_EL3: add PIE support
BL31: discard .dynsym .dynstr .hash sections to make ENABLE_PIE work
PIE: pass PIE options only to BL31
Build: support per-BL LDFLAGS
