sk98lin: fix compile warnings

sk98lin: fix compile warnings

Fix warnings:
skge.c: In function 'BoardInitMem':
skge.c:1389: warning: dereferencing type-punned pointer will break strict-aliasing rules
skge.c:1390: warning: dereferencing type-punned pointer will break strict-aliasing rules
skge.c:1391: warning: dereferencing type-punned pointer will break strict-aliasing rules
skgesirq.c: In function 'SkGePortCheckUpXmac':
skgesirq.c:1301: warning: dereferencing type-punned pointer will break strict-aliasing rules
skgesirq.c:1301: warning: dereferencing type-punned pointer will break strict-aliasing rules
skgesirq.c:1398: warning: dereferencing type-punned pointer will break strict-aliasing rules
skgesirq.c:1398: warning: dereferencing type-punned pointer will break strict-aliasing rules
skrlmt.c: In function 'SkRlmtInit':
skrlmt.c:661: warning: dereferencing type-punned pointer will break strict-aliasing rules
skxmac2.c: In function 'SkMacPromiscMode':
skxmac2.c:753: warning: dereferencing type-punned pointer will break strict-aliasing rules
skxmac2.c:753: warning: dereferencing type-punned pointer will break strict-aliasing rules
skxmac2.c: In function 'SkMacHashing':
skxmac2.c:803: warning: dereferencing type-punned pointer will break strict-aliasing rules
skxmac2.c:803: warning: dereferencing type-punned pointer will break strict-aliasing rules
skxmac2.c: In function 'SkMacFlushTxFifo':
skxmac2.c:1115: warning: dereferencing type-punned pointer will break strict-aliasing rules
skxmac2.c:1115: warning: dereferencing type-punned pointer will break strict-aliasing rules
skxmac2.c: In function 'SkMacFlushRxFifo':
skxmac2.c:1145: warning: dereferencing type-punned pointer will break strict-aliasing rules
skxmac2.c:1145: warning: dereferencing type-punned pointer will break strict-aliasing rules
skxmac2.c: In function 'SkXmInitPauseMd':
skxmac2.c:1987: warning: dereferencing type-punned pointer will break strict-aliasing rules
skxmac2.c:1987: warning: dereferencing type-punned pointer will break strict-aliasing rules
skxmac2.c: In function 'SkXmOverflowStatus':
skxmac2.c:4236: warning: dereferencing type-punned pointer will break strict-aliasing rules
skxmac2.c:4236: warning: dereferencing type-punned pointer will break strict-aliasing rules
skxmac2.c:4242: warning: dereferencing type-punned pointer will break strict-aliasing rules
skxmac2.c:4242: warning: dereferencing type-punned pointer will break strict-aliasing rules

Signed-off-by: Wolfgang Denk <wd@denx.de>
Cc: Ben Warren <biggerbadderben@gmail.com>