ARM: s3c24xx: Fix boolean expressions in osiris_dvs_notify

Fix boolean expressions by using logical AND operator '&&' instead of
bitwise operator '&'.

This issue was detected with the help of Coccinelle.

Fixes: 4fa084af ("ARM: OSIRIS: DVS (Dynamic Voltage Scaling) supoort.")
Cc: stable@vger.kernel.org
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
[krzk: Fix -Wparentheses warning]
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>