powerpc: mpc83xx: Fix timer value calculation

TBU and TBL are specified as two 32-bit registers that form a 64-bit
value, but the calculation only shifted TBU by 16 bits.

Fix this by actually shifting 32 bits.

Reviewed-by: Sinan Akman <sinan@writeme.com>
Signed-off-by: J. Neuschäfer <j.ne@posteo.net>
1 file changed