cmd: sf: prevent overwriting the reserved memory

cmd: sf: prevent overwriting the reserved memory

Added LMB API to prevent SF command from overwriting reserved
memory areas. The current SPI code does not use LMB APIs for
loading data into memory addresses. To resolve this, LMB APIs
were added to check the load address of an SF command and ensure it
does not overwrite reserved memory addresses. Similar checks are
used in TFTP, serial load, and boot code to prevent overwriting
reserved memory.

Signed-off-by: Prasad Kummari <prasad.kummari@amd.com>
Suggested-by: Sughosh Ganu <sughosh.ganu@linaro.org>