cmd: eeprom: don't truncate target address at 32-bit

On 64-bit platforms where int is 32-bit wide, the eeprom command
parse_numeric_param() routine truncates the memory address parameter to
the lower 32-bit. Make parse_numeric_param() return long to allow
read/write of addresses beyond the lower 4GB.

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>