staging: lustre: lnet: klnds: socklnd: Move extern declarations to header

This patch moves extern declarations in socklnd_lib.c to the respective
header file, 'socklnd.h'.

This patch also removes extern keyword from function declarations
since functions have the extern specifier by default.

Signed-off-by: Amitoj Kaur Chawla <amitoj1606@gmail.com>
Acked-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>