OMAP2/3 board-*.c files: read bootloader configuration earlier

Most board-*.c files read configuration data from the bootloader in
their .init_machine() function.  This needs to happen earlier, at some
point before omap2_init_common_hw() is called.  This is because a
future patch will use the bootloader serial console port information
to enable the UART clocks earlier, immediately after omap2_clk_init().
This is in turn necessary since otherwise clock tree usecounts on
clocks like dpll4_m2x2_ck will be bogus, which can cause the
currently-active console UART clock to be disabled during boot.

Signed-off-by: Paul Walmsley <paul@pwsan.com>