[ARM] S3C2443: Fix s3c2443_clkcon_enable_p() using wrong register.

s3c2443_clkcon_enable_p() was reading from the correct register
S3C2443_PCLKCON, but then writing the value back to the wrong
register S3C2443_HCLKCON.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>