USB: s3c-hsotg: modify only selected bits in S3C_PHYPWR register

S5PV210 SoCs has 2 USB PHY interfaces, both enabled by writing zero to
S3C_PHYPWR register. HS/OTG driver uses only PHY0, so do not touch bits
related to PHY1.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>