openrisc: Add R_OR1K_32_PCREL relocation type module support

To ensure the proper functioning of the jump_label test module, this patch
adds support for the R_OR1K_32_PCREL relocation type for any modules. The
implementation calculates the PC-relative offset by subtracting the
instruction location from the target value and stores the result at the
specified location.

Signed-off-by: chenmiao <chenmiao.ku@gmail.com>
Signed-off-by: Stafford Horne <shorne@gmail.com>