riscv_read_by_any_size() is redundant

[en-sc]

riscv_read_by_any_size() is used to try all available sizes when reading memory:

riscv-openocd/src/target/riscv/riscv.c

Lines 1392 to 1397 in eb9ba21

	/**
	* Read one memory item using any memory access size that will work.
	* Read larger section of memory and pick out the required portion, if needed.
	* */
	int riscv_read_by_any_size(struct target *target, target_addr_t address, uint32_t size, uint8_t *buffer)
	{

riscv_read_by_any_size() is currently used in riscv_semihosting() and in riscv_add_breakpoint() to read instructions.

There is also target_read_buffer(). It provides the same interface.
Seems like riscv_read_by_any_size() should be the implementation of target_read_buffer() (currently target_read_buffer_default() is used).