parisc: Merge ftrace C-helper and assembler functions into .text.hot section

When enabling all-branch ftrace support (CONFIG_PROFILE_ALL_BRANCHES)
the kernel gets really huge and some ftrace assembler functions like
mcount can't reach the ftrace helper functions which are written in C.
Avoid this problem of too distant branches by moving the ftrace C-helper
functions into the .text.hot section which is put in front of the
standard .text section by the linker.

Signed-off-by: Helge Deller <deller@gmx.de>