build: Drop libgcc runtime wrapper in Clang builds

This GCC specific workaround of wrapping of libgcc runtime symbols with
gcc.c is not nessary with libcompiler-rt linkage.

Change-Id: I50a2bc99d97f68a2ad2b51a92ea0e7086bab35fe
Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-on: http://review.coreboot.org/5812
Tested-by: build bot (Jenkins)
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
superio/smsc/kbc1100: Virtually rewrite support and fix mainboards

1. Remove #include .c in romstage.
2. Make romstage component symbols linker-time.
3. Provide header guards and prototypes in superio romstage support.
4. Correct function type-signatures to be static/non-static where
appropriate, avoid 'pretend optimisations' by unnecessarily inlining
functions.
5. Separate out UART enable from various other PNP hard coding

Change-Id: I9b8dad7c02d802e97db73ddf2913d5c6bb33a419
Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-on: http://review.coreboot.org/5916
Tested-by: build bot (Jenkins)
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>