mips_m4k : Fix soft breakpoint endianess handling
In order to compare data read from the target with some marcros or data defined on the host, we must transform this read data from target endianess to host endianess. target_read_memory() gets bytes from target to the host, but keeps them in _target_ endianess. This is OK if we just want to temporary keep this data on the host, like keeping breakpoint->orig_instr. But if we want to use this data for any ispections and comparisons on the host side, we must transform it to _host_ endianess, by using target_buffer_get_u32() function. Currently this transformation is missing, and check current_instr == MIPS32_SDBBP will never pass if target and host endianess differ, because current_instr will be kept in _target_ endianess and MIPS32_SDBBP will be kept in _host_ endianess, The patch fix this issue by using target_buffer_get_u32() to transform current_instr to _host_ endianess before comparison.