Makefile: Match the full path to ccache for filtering

Makefile: Match the full path to ccache for filtering

One can use ccache by keeping ccache in PATH or by providing the full
path to ccache as well. Providing the full path to ccache fails as the
current regex tries to look for ccache being the initial token during
filtering.

Do a greedy search to remove anything before ccache for regex matching.

Fixes: 04b1d84221d5 ("Makefile: fix empty MK_ARCH when using ccache")
Signed-off-by: Manorit Chawdhry <m-chawdhry@ti.com>