lm32: Replace call to write_memory with write_memory_unsigned_integer

lm32: Replace call to write_memory with write_memory_unsigned_integer

Fixes this error:

/home/emaisin/src/binutils-gdb/gdb/lm32-tdep.c: In function ‘CORE_ADDR lm32_push_dummy_call(gdbarch*, value*, regcache*, CORE_ADDR, int, value**, CORE_ADDR, int, CORE_ADDR)’:
/home/emaisin/src/binutils-gdb/gdb/lm32-tdep.c:292:59: error: invalid conversion from ‘void*’ to ‘const gdb_byte* {aka const unsigned char*}’ [-fpermissive]
    write_memory (sp, (void *) &val, TYPE_LENGTH (arg_type));
                                                           ^
In file included from /home/emaisin/src/binutils-gdb/gdb/lm32-tdep.c:29:0:
/home/emaisin/src/binutils-gdb/gdb/gdbcore.h:107:13: error:   initializing argument 2 of ‘void write_memory(CORE_ADDR, const gdb_byte*, ssize_t)’ [-fpermissive]
 extern void write_memory (CORE_ADDR memaddr, const gdb_byte *myaddr,
             ^

gdb/ChangeLog:

	* lm32-tdep.c (lm32_push_dummy_call): Replace call to
	write_memory with write_memory_unsigned_integer.