opensbi: bump to 1.5

opensbi: bump to 1.5

This release has:
- SBI debug triggers (DBTR) extension (Experimental)
- Support to specify coldboot harts in DT
- Relocatable FW_JUMP_ADDR and FW_JUMP_FDT_ADDR
- Smcsrind and Smcdeleg extensions support
- SBIUnit testing framework
- Initial domain context management support
- Platform specific load/store emulation callbacks
-  New trap context
- Improved sbi_trap_error() to dump state in a nested trap
- SBI supervisor software events (SSE) extension (Experimental)
- Simplified wait_for_coldboot() implementation
- Early wakeup of non-coldboot HART in the coldboot path
- Sophgo CV18XX/SG200X series support
- APLIC delegation DT property fix
- Svade and Svadu extensions support
- SBI firmware features (FWFT) extension (Experimental)

Overall, this release mainly adds more ISA extensions, SBI
extensions and other improvements.

Signed-off-by: Thomas Perrot <thomas.perrot@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>