staging: et131x: Remove some forward declarations

Moved functions in et131x.c file to remove the following forward
declarations:

et131x_align_allocated_memory
et131x_disable_interrupts
et131x_enable_interrupts
et131x_error_timer_handler

Signed-off-by: Mark Einon <mark.einon@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>