ppc4xx: Fix 440EPx bug in reconfigure_pll()

This patch fixes a bug in reconfigure_pll(), where the detection of
the current bootstrap option is wrong. The ICS bits where incorrectly
shifted. This bug was found on the lwmon5 board, which uses bootstrap
option H (I2C bootstrap EEPROM).

Additionally a bit of code was moved into the if statement, since its
only used after later on. No need to run this code all the time.

Also, a few empty lines are added to make the code better readable.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Rupjyoti Sarmah <rsarmah@amcc.com>
Cc: Victor Gallardo <vgallardo@appliedmicro.com>