Expand heap to 64KB so that bootxx can load bootxxx from 32KB blocksize ffs.

Tested on TT030 with 32GB SSD via SATA->IDE->SCSI converters.
Should be pulled up to netbsd-7 and netbsd-6 branches..
Separate linker script argument (${LINKSCRIPT}) from ${LINKFORMAT}

${LINKFORMAT} specifies ABI options, and used for ld -r.  ${LINKSCRIPT} (-T
ldscript) is used only for final link.
Don't sort objects for modular build.
config(1): Sort objects by weight in modular build

Sort per-module kernel objects (*.ko) by dependency weight.  Important modules
are placed in lower addresses.  The ``machdep'' module will be always placed
in the lowest.

(At this moment, the order is not exact because dependency information is
incomplete in config files (files.*).  Thus ``sysmon_power.ko'' comes lower
than ``machdep.ko'' and/or ``uvm.ko''; but still much better than alphabetical
sort.)