powerpc/boot: Change the macro of Boot from SRIO and PCIE master module

Currently, the macro "CONFIG_SYS_FSL_SRIO_PCIE_BOOT_MASTER" can enable
the master module of Boot from SRIO and PCIE on a platform. But this
is not a silicon feature, it's just a specific booting mode based on
the SRIO and PCIE interfaces. So it's inappropriate to put the macro
into the file arch/powerpc/include/asm/config_mpc85xx.h.

Change the macro "CONFIG_SYS_FSL_SRIO_PCIE_BOOT_MASTER" to
"CONFIG_SRIO_PCIE_BOOT_MASTER", remove them from
arch/powerpc/include/asm/config_mpc85xx.h file, and add those macros
in configuration header file of each board which can support the
master module of Boot from SRIO and PCIE.

Signed-off-by: Liu Gang <Gang.Liu@freescale.com>
Signed-off-by: Andy Fleming <afleming@freescale.com>